diff --git a/.github/actions/node-setup/action.yml b/.github/actions/node-setup/action.yml
new file mode 100644
index 0000000..9848f55
--- /dev/null
+++ b/.github/actions/node-setup/action.yml
@@ -0,0 +1,25 @@
+name: "Setup"
+
+runs:
+  using: "composite"
+  steps:
+    # https://github.com/actions/cache/blob/main/examples.md#node---yarn
+    - name: Get yarn cache directory path
+      id: yarn-cache-dir-path
+      run: echo "::set-output name=dir::$(yarn cache dir)"
+      shell: bash
+
+    - name: Node cache
+      id: node-cache
+      uses: actions/cache@v3
+      with:
+        path: |
+          ${{ steps.yarn-cache-dir-path.outputs.dir }}
+          "**/node_modules"
+        key: ${{ runner.os }}-node-${{ hashFiles('**/yarn.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-node-
+
+    - name: Package Install
+      run: yarn install
+      shell: bash
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 06d708a..853e83f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,20 +21,10 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
-      - name: Node cache
-        id: node-cache
-        uses: actions/cache@v2
-        with:
-          path: node_modules
-          key: ${{ runner.os }}-node-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-node-
-
-      - name: Package Install
-        if: steps.node-cache.outputs.cache-hit != 'true'
-        run: yarn install
+      - name: Setup
+        uses: ./.github/actions/node-setup
 
       - name: Build
         run: yarn build
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 9788e49..4f637e8 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -7,7 +7,8 @@ jobs:
   sync-branches:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
+        fetch-depth: 0
 
       - name: Merge master -> photon-style
         uses: devmasx/merge-branch@1.4.0
@@ -38,7 +39,7 @@ jobs:
           - name: "Lepton-Proton-Style"
             branch: "proton-style"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           ref: ${{ matrix.branch }}
 
diff --git a/CREDITS b/CREDITS
index b5a5812..9b18c90 100644
--- a/CREDITS
+++ b/CREDITS
@@ -7,6 +7,9 @@
 ----------
     Major Contributors
 
+N: 2641a40fd44383320adde4b027a1d0b03bd550
+W: https://github.com/2641a40fd44383320adde4b027a1d0b03bd550
+
 N: AveYo
 E: aveyo@yahoo.com
 W: https://github.com/AveYo
@@ -26,6 +29,10 @@ N: Jani Haiko
 E: haiko.jani@gmail.com
 W: https://github.com/ojaha065
 
+N: Jiho Lee
+E: optional.int@kakao.com
+W: https://github.com/DPS0340
+
 N: kanlukasz
 W: https://github.com/kanlukasz
 
@@ -39,9 +46,6 @@ W: https://www.oss.kr/
 ----------
     Contributors
 
-N: 2641a40fd44383320adde4b027a1d0b03bd550
-W: https://github.com/2641a40fd44383320adde4b027a1d0b03bd550
-
 N: 7k5x
 E: 7k5xlp0onfire@gmail.com
 W: https://github.com/7k5x
diff --git a/README.org b/README.org
index 8a2782f..d4ae800 100644
--- a/README.org
+++ b/README.org
@@ -186,6 +186,7 @@ Thanks to all sponsors & contributors to this project for providing help and dev
 
 [[https://www.oss.kr/][https://user-images.githubusercontent.com/25581533/203210367-9f2eed69-666a-4218-acde-128892aa09d8.png]]
 [[https://github.com/ojaha065][@@html:<img src="https://avatars.githubusercontent.com/u/37581768?s=60&v=4"/>@@]]
+[[https://github.com/DPS0340][@@html:<img src="https://avatars.githubusercontent.com/u/32592965?s=60&v=4"/>@@]]
 [[https://github.com/kanlukasz][@@html:<img src="https://avatars.githubusercontent.com/u/30685349?s=60&v=4"/>@@]]
 [[https://github.com/nikkehtine][@@html:<img src="https://avatars.githubusercontent.com/u/27138416?s=60&v=4"/>@@]]
 
diff --git a/__tests__/native_menu.test.scss b/__tests__/native_menu.test.scss
index 7b6d005..ba7189b 100644
--- a/__tests__/native_menu.test.scss
+++ b/__tests__/native_menu.test.scss
@@ -9,6 +9,9 @@
         @include native_menu.NativeMenu {
           @include example;
         }
+        @include native_menu.NativeMenuPopup {
+          @include example;
+        }
         @include native_menu.Win10_NativeMenu {
           @include example;
         }
@@ -17,6 +20,10 @@
         @supports -moz-bool-pref("widget.macos.native-context-menus") or -moz-bool-pref("widget.gtk.native-context-menus") {
           @include example;
         }
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup),
+        menupopup:not([placespopup="true"]) {
+          @include example;
+        }
         @media not (-moz-windows-non-native-menus) {
           @include example;
         }
diff --git a/css/leptonChrome.css b/css/leptonChrome.css
index 8c8358d..d9efbf7 100644
--- a/css/leptonChrome.css
+++ b/css/leptonChrome.css
@@ -49,6 +49,12 @@
   #widget-overflow-mainView #zoom-in-button > .toolbarbutton-icon {
     padding-inline-start: 0px !important;
   }
+  /*= Subview button, Menu's right padding #597 ================================*/
+  .subviewbutton.toolbaritem-combined-buttons:not([shortcut]),
+  .subviewbutton.subviewbutton-nav:not([shortcut]),
+  menu.subviewbutton {
+    padding-inline-end: 0 !important;
+  }
   /*= Icon Fill Color ==========================================================*/
   :root:-moz-lwtheme {
     /* Auto create --lwt-toolbarbutton-icon-fill-attention, fix for nightly default theme
@@ -273,25 +279,27 @@
     }
   }
   @media (-moz-os-version: windows-win7), (-moz-platform: windows-win7) {
-    menu[_moz-menuactive="true"],
-    menuitem[_moz-menuactive="true"] {
-      background-color: color-mix(in srgb, -moz-menuhover 5%, transparent) !important;
-      border-color: color-mix(in srgb, -moz-menuhover 60%, transparent) !important;
-    }
-    menu[_moz-menuactive="true"][disabled="true"],
-    menuitem[_moz-menuactive="true"][disabled="true"] {
-      background-color: color-mix(in srgb, currentColor 5%, transparent) !important;
-      border-color: color-mix(in srgb, currentColor 60%, transparent) !important;
-    }
-    /* Remove text shadow */
-    :root:-moz-lwtheme #toolbar-menubar {
-      text-shadow: unset !important;
-      /* Original: 0 0 .5em white, 0 0 .5em white, 0 1px 0 rgba(255, 255, 255, .4) */
-    }
-    /* Remove Color */
-    :root:-moz-lwtheme #main-menubar:not(:-moz-window-inactive) {
-      background-color: unset !important; /* Original: rgba(255, 255, 255, .5) */
-      color: unset !important; /* Original: black */
+    @media (-moz-windows-classic: 0) {
+      menu[_moz-menuactive="true"],
+      menuitem[_moz-menuactive="true"] {
+        background-color: color-mix(in srgb, -moz-menuhover 5%, transparent) !important;
+        border-color: color-mix(in srgb, -moz-menuhover 60%, transparent) !important;
+      }
+      menu[_moz-menuactive="true"][disabled="true"],
+      menuitem[_moz-menuactive="true"][disabled="true"] {
+        background-color: color-mix(in srgb, currentColor 5%, transparent) !important;
+        border-color: color-mix(in srgb, currentColor 60%, transparent) !important;
+      }
+      /* Remove text shadow */
+      :root:-moz-lwtheme #toolbar-menubar {
+        text-shadow: unset !important;
+        /* Original: 0 0 .5em white, 0 0 .5em white, 0 1px 0 rgba(255, 255, 255, .4) */
+      }
+      /* Remove Color */
+      :root:-moz-lwtheme #main-menubar:not(:-moz-window-inactive) {
+        background-color: unset !important; /* Original: rgba(255, 255, 255, .5) */
+        color: unset !important; /* Original: black */
+      }
     }
   }
   @media (-moz-os-version: windows-win8), (-moz-platform: windows-win8) {
@@ -310,15 +318,15 @@
   @media (-moz-os-version: windows-win10), (-moz-platform: windows-win10) {
     @media not (-moz-windows-non-native-menus) {
       menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) menu[_moz-menuactive="true"],
-      menupopup:not([placespopup="true"]) menu[_moz-menuactive="true"],
       menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) menuitem[_moz-menuactive="true"],
+      menupopup:not([placespopup="true"]) menu[_moz-menuactive="true"],
       menupopup:not([placespopup="true"]) menuitem[_moz-menuactive="true"] {
         background-color: #91c9f7 !important;
         border-color: transparent !important;
       }
       menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) menu[_moz-menuactive="true"][disabled="true"],
-      menupopup:not([placespopup="true"]) menu[_moz-menuactive="true"][disabled="true"],
       menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) menuitem[_moz-menuactive="true"][disabled="true"],
+      menupopup:not([placespopup="true"]) menu[_moz-menuactive="true"][disabled="true"],
       menupopup:not([placespopup="true"]) menuitem[_moz-menuactive="true"][disabled="true"] {
         background-color: color-mix(in srgb, currentColor 9%, transparent) !important;
         border-color: transparent !important;
@@ -2243,7 +2251,6 @@
       --in-content-border-color: color-mix(in srgb, currentColor 41%, transparent) !important;
     }
     #viewGroup > radio {
-      border-radius: 8px !important;
       padding: var(--in-content-button-vertical-padding) var(--in-content-button-horizontal-padding) !important;
       margin: 4px !important;
       list-style-image: none !important;
@@ -2255,6 +2262,11 @@
       fill: currentColor !important;
       color: var(--in-content-deemphasized-text) !important; /* FieldText */
     }
+    @supports not -moz-bool-pref("userChrome.rounding.square_button") {
+      #viewGroup > radio {
+        border-radius: 8px !important;
+      }
+    }
     #viewGroup > radio:hover {
       background-color: var(--in-content-button-background-hover) !important; /* #E0E8F6; */
     }
@@ -2441,6 +2453,11 @@
         padding: 5px !important;
         border-radius: 4px !important;
       }
+      @supports -moz-bool-pref("userChrome.rounding.square_button") {
+        #placesToolbar > toolbarbutton {
+          border-radius: 0 !important;
+        }
+      }
       #placesToolbar > toolbarbutton[disabled] {
         opacity: 0.6 !important;
       }
@@ -2463,11 +2480,16 @@
       #placesMenu > menu {
         appearance: none !important;
         color: var(--organizer-color) !important;
-        border-radius: 4px !important;
         padding-block: 5px !important;
         padding-inline-start: 5px !important;
+        border-radius: 4px !important;
         margin-inline-end: 2px !important;
       }
+      @supports -moz-bool-pref("userChrome.rounding.square_button") {
+        #placesMenu > menu {
+          border-radius: 0 !important;
+        }
+      }
       #placesMenu > menu[_moz-menuactive="true"],
       #placesMenu > menu:hover {
         background-color: var(--organizer-hover-background) !important;
@@ -2494,6 +2516,12 @@
         padding-block: 2px !important;
         min-height: 24px !important;
       }
+      @supports -moz-bool-pref("userChrome.rounding.square_field") {
+        #searchFilter,
+        #detailsPane html|input {
+          border-radius: 0 !important;
+        }
+      }
       #searchFilter[focused] {
         box-shadow: var(--organizer-toolbar-field-focus-box-shadow) !important;
         background-color: var(--organizer-toolbar-field-background-focused) !important;
@@ -2635,6 +2663,12 @@
         -moz-context-properties: fill !important;
         fill: currentColor !important;
       }
+      @supports -moz-bool-pref("userChrome.rounding.square_button") {
+        #editBookmarkPanelRows .expander-up,
+        #editBookmarkPanelRows .expander-down {
+          border-radius: 0 !important;
+        }
+      }
       #editBookmarkPanelRows .expander-up:hover,
       #editBookmarkPanelRows .expander-down:hover {
         background-color: var(--organizer-hover-background) !important;
@@ -2668,6 +2702,11 @@
         min-height: 20px !important;
         padding-inline: 4px !important;
       }
+      @supports -moz-bool-pref("userChrome.rounding.square_field") {
+        #places input {
+          border-radius: 0 !important;
+        }
+      }
       #places input:focus {
         outline: 2px solid var(--organizer-outline-color) !important;
         outline-offset: -1px !important;
@@ -2686,6 +2725,11 @@
         border: 1px solid var(--organizer-border-color) !important;
         border-radius: 4px !important;
       }
+      @supports -moz-bool-pref("userChrome.rounding.square_field") {
+        #editBMPanel_tagsSelectorRow > richlistbox {
+          border-radius: 0 !important;
+        }
+      }
       #editBMPanel_tagsSelectorRow > richlistbox > richlistitem {
         border: 1px solid transparent !important;
       }
@@ -2734,15 +2778,10 @@
   #identity-popup-clear-sitedata-button,
   #identity-popup-more-info,
   #unified-extensions-manage-extensions,
-  .unified-extensions-item-open-menu {
+  .unified-extensions-item-open-menu,
+  .unified-extensions-item-menu-button.subviewbutton {
     cursor: pointer !important;
   }
-  /* TODO: For now, fxa-menu doesn't show any status.
-             (JS required, observe .syncNowBtn status)
-    #PanelUI-fxa-menu-syncnow-button[syncstatus="active"] {
-      cursor: progress !important;
-    }
-    */
 }
 /*= Panel UI Button Separator ================================================*/
 @supports -moz-bool-pref("userChrome.decoration.panel_button_separator") {
@@ -3064,13 +3103,15 @@
   .urlbarView-button,
   .urlbarView-tip-button,
   .urlbarView-action,
+  .tab-close-button,
   toolbarbutton.bookmark-item:not(.subviewbutton),
   #sidebar-switcher-target {
     --toolbarbutton-border-radius: 0; /* Original: 4px */
   }
   button,
   findbar toolbarbutton,
-  .notification-button {
+  .notification-button,
+  #main-menubar > menu {
     border-radius: 0 !important;
   }
 }
@@ -3081,6 +3122,11 @@
     --tab-border-radius: var(--toolbarbutton-border-radius);
   }
 }
+@supports -moz-bool-pref("userChrome.rounding.square_dialog") {
+  .dialogBox {
+    border-radius: 0 !important;
+  }
+}
 @supports -moz-bool-pref("userChrome.rounding.square_panel") {
   :root {
     --arrowpanel-border-radius: 0 !important;
@@ -3093,7 +3139,7 @@
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_menupopup") {
-  xul|menupopup {
+  menupopup {
     --panel-border-radius: 0px !important;
     border-radius: 0 !important;
   }
@@ -3109,6 +3155,7 @@
   html|select[size][multiple],
   xul|listheader,
   xul|richlistbox,
+  xul|menulist,
   html|input {
     border-radius: 0 !important;
   }
@@ -3124,8 +3171,23 @@
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_checklabel") {
-  .checkbox-check,
-  xul|*.radio-check {
+  .checkbox-check {
+    border-radius: 0 !important;
+  }
+}
+/*= Library ==============================================================*/
+@supports -moz-bool-pref("userChrome.rounding.square_button") {
+  #placesToolbar > toolbarbutton,
+  #placesMenu > menu,
+  #editBookmarkPanelRows .expander-up,
+  #editBookmarkPanelRows .expander-down {
+    border-radius: 0 !important;
+  }
+}
+@supports -moz-bool-pref("userChrome.rounding.square_field") {
+  #searchFilter,
+  #detailsPane html|input,
+  #places input #editBMPanel_tagsSelectorRow > richlistbox {
     border-radius: 0 !important;
   }
 }
@@ -3754,13 +3816,16 @@
 /*= Panel - Reduce padding ===================================================*/
 @supports -moz-bool-pref("userChrome.padding.panel") {
   :root {
-    --arrowpanel-menuitem-margin: 0 var(--arrowpanel-menuicon-padding, 8px) !important; /* Original: 0 8px */
+    --arrowpanel-menuitem-margin-block: 0; /* FF 102 compatibility */
+    --arrowpanel-menuitem-margin-inline: 8px;
+    --arrowpanel-menuitem-margin: var(--arrowpanel-menuitem-margin-block) var(--arrowpanel-menuitem-margin-inline) !important; /* Original: 0 8px */
     --arrowpanel-menuitem-padding-block: 5px !important; /* Original: 8px */
     --arrowpanel-menuitem-padding-inline: 5px !important; /* Original: 8px */
     --arrowpanel-menuitem-padding: var(--arrowpanel-menuitem-padding-block) var(--arrowpanel-menuitem-padding-inline) !important; /* Compatibility */
     --arrowpanel-padding: 0.8em !important; /* Original: 16px or .cui-widget-panel, .cui-widget-panel::part(arrowcontent) => 4px 0 */
   }
   :root[uidensity="compact"] {
+    --arrowpanel-menuitem-margin-inline: 4px; /* FF 102 compatibility */
     --arrowpanel-menuitem-padding-block: 3px !important;
     --arrowpanel-menuitem-padding-inline: 3px !important;
   }
@@ -3768,6 +3833,9 @@
     --arrowpanel-menuitem-padding-block: 8px !important; /* Original: 8px */
     --arrowpanel-menuitem-padding-inline: 8px !important; /* Original: 8px */
   }
+  .all-tabs-item {
+    margin: var(--arrowpanel-menuitem-margin) !important;
+  }
   @supports not -moz-bool-pref("userChrome.icon.disabled") {
     @supports not -moz-bool-pref("userChrome.icon.panel") {
       .subviewbutton {
@@ -3775,6 +3843,9 @@
       }
     }
   }
+  .unified-extensions-item-menu-button.subviewbutton {
+    padding: 8px !important; /* Original: var(--arrowpanel-menuitem-padding-inline) */
+  }
 }
 @supports -moz-bool-pref("userChrome.padding.panel_header") {
   .panel-header {
@@ -8723,39 +8794,42 @@
 @supports -moz-bool-pref("userChrome.autohide.back_button") or -moz-bool-pref("userChrome.autohide.forward_button") {
   :root {
     --uc-toolbarbutton-hide-size: calc(
-      -1 * (16px + (2 * var(--toolbarbutton-outer-padding) + var(--toolbarbutton-inner-padding)))
+      -1 * (16px + (2 * (var(--toolbarbutton-outer-padding) + var(--toolbarbutton-inner-padding))))
     );
   }
 }
-@supports -moz-bool-pref("userChrome.autohide.back_button") {
-  #back-button[disabled="true"] {
-    margin-left: var(--uc-toolbarbutton-hide-size) !important;
-    opacity: 0 !important;
-    pointer-events: none;
-  }
-  @media (prefers-reduced-motion: no-preference) {
-    #back-button {
-      transition-property: background-color, opacity, margin-left !important;
+@-moz-document url("chrome://browser/content/browser.xhtml")
+{
+  @supports -moz-bool-pref("userChrome.autohide.back_button") {
+    :root:not([customizing="true"]) #back-button[disabled="true"] {
+      margin-left: var(--uc-toolbarbutton-hide-size) !important;
+      opacity: 0 !important;
+      pointer-events: none;
     }
-    #back-button[disabled="true"] {
-      transition: background-color 1s var(--animation-easing-function), opacity 1s var(--animation-easing-function),
-        margin-left 0.5s ease !important;
+    @media (prefers-reduced-motion: no-preference) {
+      #back-button {
+        transition-property: background-color, opacity, margin-left !important;
+      }
+      #back-button[disabled="true"] {
+        transition: background-color 1s var(--animation-easing-function), opacity 1s var(--animation-easing-function),
+          margin-left 0.5s ease !important;
+      }
     }
   }
-}
-@supports -moz-bool-pref("userChrome.autohide.forward_button") {
-  #forward-button[disabled="true"] {
-    margin-left: var(--uc-toolbarbutton-hide-size) !important;
-    opacity: 0 !important;
-    pointer-events: none;
-  }
-  @media (prefers-reduced-motion: no-preference) {
-    #forward-button {
-      transition-property: background-color, opacity, margin-left !important;
+  @supports -moz-bool-pref("userChrome.autohide.forward_button") {
+    :root:not([customizing="true"]) #forward-button[disabled="true"] {
+      margin-left: var(--uc-toolbarbutton-hide-size) !important;
+      opacity: 0 !important;
+      pointer-events: none;
     }
-    #forward-button[disabled="true"] {
-      transition: background-color 1s var(--animation-easing-function), opacity 1s var(--animation-easing-function),
-        margin-left 0.5s ease !important;
+    @media (prefers-reduced-motion: no-preference) {
+      #forward-button {
+        transition-property: background-color, opacity, margin-left !important;
+      }
+      #forward-button[disabled="true"] {
+        transition: background-color 1s var(--animation-easing-function), opacity 1s var(--animation-easing-function),
+          margin-left 0.5s ease !important;
+      }
     }
   }
 }
@@ -9592,6 +9666,11 @@
     }
   }
   @supports -moz-bool-pref("userChrome.hidden.urlbar_iconbox.label_only") {
+    #identity-box[pageproxystate="valid"].notSecureText,
+    #identity-box[pageproxystate="valid"].chromeUI,
+    #identity-box[pageproxystate="valid"].extensionPage {
+      margin-inline-end: var(--identity-box-margin-inline) !important;
+    }
     #identity-box[pageproxystate="valid"].chromeUI #identity-icon-box:not(:hover),
     #identity-box[pageproxystate="valid"].extensionPage #identity-icon-box:not(:hover) {
       background-color: transparent !important;
@@ -9797,6 +9876,16 @@
     }
   }
   /** Panel - Icons *************************************************************/
+  :root {
+    --uc-sidebar-icon: url("chrome://browser/skin/sidebars.svg");
+    --uc-sidebar-icon-reverse: url("chrome://browser/skin/sidebars-right.svg");
+  }
+  @supports selector(:has(a)) {
+    :root:has(#sidebar-box[positionend="true"]) {
+      --uc-sidebar-icon: url("chrome://browser/skin/sidebars-right.svg");
+      --uc-sidebar-icon-reverse: url("chrome://browser/skin/sidebars.svg");
+    }
+  }
   @supports -moz-bool-pref("userChrome.icon.panel") {
     /*= Padding ==================================================================*/
     :root {
@@ -10257,6 +10346,12 @@
       list-style-image: url("chrome://global/skin/icons/settings.svg");
     }
     /*= BMB_bookmarksPopup =======================================================*/
+    #BMB_viewBookmarksSidebar {
+      --menuitem-image: var(--uc-sidebar-icon);
+    }
+    #BMB_viewBookmarksSidebar[data-l10n-args='{"isVisible":true}'] {
+      --menuitem-image: url("chrome://global/skin/icons/close.svg");
+    }
     #BMB_bookmarksShowAllTop,
     #BMB_bookmarksShowAll {
       --menuitem-image: url("chrome://browser/skin/bookmark-star-on-tray.svg");
@@ -10319,11 +10414,7 @@
       list-style-image: url("chrome://browser/skin/tab.svg");
     }
     #sidebar-reverse-position {
-      list-style-image: url("chrome://browser/skin/sidebars-right.svg");
-    }
-    #sidebar-box[positionend="true"] #sidebar-reverse-position {
-      /* Can't apply this. shadow dom */
-      list-style-image: url("chrome://browser/skin/sidebars.svg");
+      list-style-image: var(--uc-sidebar-icon-reverse);
     }
     #sidebarMenu-popup > .subviewbutton[data-l10n-id="sidebar-menu-close"] {
       list-style-image: url("chrome://global/skin/icons/close.svg");
@@ -10443,6 +10534,11 @@
       :root {
         --context-menu-background-padding-default: 2px;
       }
+      @media (-moz-windows-classic) {
+        :root {
+          --context-menu-background-padding-default: -0.5px;
+        }
+      }
     }
     @media (-moz-os-version: windows-win8), (-moz-platform: windows-win8) {
       :root {
@@ -10489,6 +10585,45 @@
           --context-menu-background-padding: 3px;
           --menu-background-padding-default: 0px;
         }
+        @supports -moz-bool-pref("userChrome.compatibility.os.win11") {
+          :root {
+            --context-menu-background-padding: 5px;
+          }
+        }
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic > .menu-iconic-left,
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menuitem-iconic > .menu-iconic-left,
+        menupopup:not([placespopup="true"]) .menu-iconic > .menu-iconic-left,
+        menupopup:not([placespopup="true"]) .menuitem-iconic > .menu-iconic-left {
+          appearance: none !important;
+          padding-block: 0 !important;
+          padding-inline-start: 5px !important;
+          margin-inline-end: 8px !important;
+        }
+        @supports -moz-bool-pref("userChrome.compatibility.os.win11") {
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic > .menu-iconic-left,
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menuitem-iconic > .menu-iconic-left,
+          menupopup:not([placespopup="true"]) .menu-iconic > .menu-iconic-left,
+          menupopup:not([placespopup="true"]) .menuitem-iconic > .menu-iconic-left {
+            box-sizing: content-box;
+          }
+        }
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-accel,
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic-accel,
+        menupopup:not([placespopup="true"]) .menu-accel,
+        menupopup:not([placespopup="true"]) .menu-iconic-accel {
+          box-sizing: content-box;
+          min-height: 16px;
+        }
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-accel,
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic-accel,
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-text,
+        menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic-text,
+        menupopup:not([placespopup="true"]) .menu-accel,
+        menupopup:not([placespopup="true"]) .menu-iconic-accel,
+        menupopup:not([placespopup="true"]) .menu-text,
+        menupopup:not([placespopup="true"]) .menu-iconic-text {
+          padding-block: 0 !important;
+        }
       }
       :not(menu, #ContentSelectDropdown, #context-navigation)
         > menupopup
@@ -10610,9 +10745,14 @@
       menupopup:is(#BMB_bookmarksPopup) menu:not(.menu-iconic),
       #PersonalToolbar menupopup[placespopup="true"] menuitem:not(.menuitem-iconic, [disabled="true"]),
       #PersonalToolbar menupopup[placespopup="true"] menu:not(.menu-iconic) {
-        margin-inline: var(--arrowpanel-menuitem-padding-inline) !important;
-        padding-inline-start: calc(var(--arrowpanel-menuicon-padding) + var(--context-menu-text-padding)) !important;
-        background-position: var(--uc-menu-background-position) calc(var(--arrowpanel-menuicon-padding)) center !important;
+        --arrowpanel-bookmark-menuicon-padding: calc(
+          var(--arrowpanel-menuicon-padding) - var(--arrowpanel-menuitem-margin-inline)
+        );
+        margin-inline-start: var(--arrowpanel-menuitem-margin-inline) !important;
+        padding-inline-start: calc(
+          var(--arrowpanel-bookmark-menuicon-padding) + var(--context-menu-text-padding)
+        ) !important;
+        background-position: var(--uc-menu-background-position) var(--arrowpanel-bookmark-menuicon-padding) center !important;
       }
     }
     /* Linux */
@@ -11643,7 +11783,7 @@
         --menuitem-image: url("../icons/toolbar.svg");
       }
       #viewSidebarMenuMenu {
-        --menuitem-image: url("chrome://browser/skin/sidebars.svg");
+        --menuitem-image: var(--uc-sidebar-icon);
       }
       #viewFullZoomMenu {
         --menuitem-image: url("../icons/screenshot.svg");
diff --git a/css/leptonContent.css b/css/leptonContent.css
index 6ad5f53..0535be6 100644
--- a/css/leptonContent.css
+++ b/css/leptonContent.css
@@ -1708,6 +1708,13 @@
       /* Ensure font-size isn't overridden by widget styling (e.g. in forms.css) */
       font-size: 1em !important;
     }
+    @supports -moz-bool-pref("userChrome.rounding.square_button") {
+      button,
+      select,
+      input[type="color"] {
+        border-radius: 0 !important;
+      }
+    }
     button {
       font-weight: 600 !important;
       /* Use the same margin of other elements for the alignment */
@@ -1781,6 +1788,11 @@
       margin-inline: 0 6px !important;
       flex-shrink: 0 !important; /* avoid shrinking inside flex container */
     }
+    @supports -moz-bool-pref("userChrome.rounding.square_checklabel") {
+      input[type="checkbox"] {
+        border-radius: 0 !important;
+      }
+    }
     input[type="checkbox"]:enabled:hover {
       background-color: var(--checkbox-unchecked-hover-bgcolor) !important;
     }
@@ -2234,6 +2246,11 @@
           padding: 5px !important;
           border-radius: 4px !important;
         }
+        @supports -moz-bool-pref("userChrome.rounding.square_button") {
+          #placesToolbar > toolbarbutton {
+            border-radius: 0 !important;
+          }
+        }
         #placesToolbar > toolbarbutton[disabled] {
           opacity: 0.6 !important;
         }
@@ -2256,11 +2273,16 @@
         #placesMenu > menu {
           appearance: none !important;
           color: var(--organizer-color) !important;
-          border-radius: 4px !important;
           padding-block: 5px !important;
           padding-inline-start: 5px !important;
+          border-radius: 4px !important;
           margin-inline-end: 2px !important;
         }
+        @supports -moz-bool-pref("userChrome.rounding.square_button") {
+          #placesMenu > menu {
+            border-radius: 0 !important;
+          }
+        }
         #placesMenu > menu[_moz-menuactive="true"],
         #placesMenu > menu:hover {
           background-color: var(--organizer-hover-background) !important;
@@ -2287,6 +2309,12 @@
           padding-block: 2px !important;
           min-height: 24px !important;
         }
+        @supports -moz-bool-pref("userChrome.rounding.square_field") {
+          #searchFilter,
+          #detailsPane html|input {
+            border-radius: 0 !important;
+          }
+        }
         #searchFilter[focused] {
           box-shadow: var(--organizer-toolbar-field-focus-box-shadow) !important;
           background-color: var(--organizer-toolbar-field-background-focused) !important;
@@ -2428,6 +2456,12 @@
           -moz-context-properties: fill !important;
           fill: currentColor !important;
         }
+        @supports -moz-bool-pref("userChrome.rounding.square_button") {
+          #editBookmarkPanelRows .expander-up,
+          #editBookmarkPanelRows .expander-down {
+            border-radius: 0 !important;
+          }
+        }
         #editBookmarkPanelRows .expander-up:hover,
         #editBookmarkPanelRows .expander-down:hover {
           background-color: var(--organizer-hover-background) !important;
@@ -2461,6 +2495,11 @@
           min-height: 20px !important;
           padding-inline: 4px !important;
         }
+        @supports -moz-bool-pref("userChrome.rounding.square_field") {
+          #places input {
+            border-radius: 0 !important;
+          }
+        }
         #places input:focus {
           outline: 2px solid var(--organizer-outline-color) !important;
           outline-offset: -1px !important;
@@ -2479,6 +2518,11 @@
           border: 1px solid var(--organizer-border-color) !important;
           border-radius: 4px !important;
         }
+        @supports -moz-bool-pref("userChrome.rounding.square_field") {
+          #editBMPanel_tagsSelectorRow > richlistbox {
+            border-radius: 0 !important;
+          }
+        }
         #editBMPanel_tagsSelectorRow > richlistbox > richlistitem {
           border: 1px solid transparent !important;
         }
@@ -2712,6 +2756,117 @@
     }
   }
 }
+/** Rounding ******************************************************************/
+@supports -moz-bool-pref("userChrome.rounding.square_button") {
+  @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/preferences/dialogs")
+  {
+    button,
+    .close-icon,
+    .action-icon::before,
+    #categories > .category,
+    .sidebar-footer-link {
+      border-radius: 0 !important;
+    }
+  }
+  @-moz-document url-prefix("about:debugging") {
+    .sidebar-item {
+      border-radius: 0 !important;
+    }
+  }
+  @-moz-document url-prefix("chrome://browser/content/places/places.xhtml"), url-prefix("about:downloads")
+  {
+    .downloadButton > .button-box {
+      border-radius: 0 !important;
+    }
+  }
+  @-moz-document url-prefix("about:protections") {
+    #manage-protections,
+    #sign-up-for-monitor-link,
+    #get-proxy-extension-link,
+    #get-vpn-link,
+    #vpn-banner-link,
+    .monitor-partial-breaches-link-wrapper,
+    .monitor-breaches-link-wrapper {
+      border-radius: 0 !important;
+    }
+  }
+}
+@supports -moz-bool-pref("userChrome.rounding.square_dialog") {
+  @-moz-document url-prefix("about:") {
+    .dialogBox {
+      border-radius: 0 !important;
+    }
+  }
+  @-moz-document url("about:home"), url("about:newtab") {
+    .modal {
+      border-radius: 0 !important;
+    }
+  }
+}
+@supports -moz-bool-pref("userChrome.rounding.square_checklabel") {
+  @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/preferences/dialogs")
+  {
+    input[type="checkbox"]:not(.toggle-button),
+    .checkbox-check {
+      border-radius: 0 !important;
+    }
+  }
+}
+@supports -moz-bool-pref("userChrome.rounding.square_field") {
+  @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/preferences/dialogs")
+  {
+    input:is([type="email"], [type="tel"], [type="text"], [type="password"], [type="url"], [type="number"]),
+    textarea,
+    select,
+    menulist,
+    search-textbox {
+      border-radius: 0 !important;
+    }
+  }
+  @-moz-document url-prefix("about:debugging") {
+    .default-input {
+      border-radius: 0 !important;
+    }
+  }
+  @-moz-document url("about:home"), url("about:newtab") {
+    .search-wrapper .search-handoff-button,
+    .search-wrapper input {
+      border-radius: 0 !important;
+    }
+  }
+}
+@supports -moz-bool-pref("userChrome.rounding.square_menupopup") {
+  @-moz-document url-prefix("about:"), url-prefix("chrome://")
+  {
+    menupopup {
+      --panel-border-radius: 0 !important;
+    }
+  }
+  @-moz-document url("about:home"), url("about:newtab") {
+    .context-menu {
+      border-radius: 0 !important;
+    }
+  }
+}
+@-moz-document url("chrome://browser/content/places/places.xhtml")
+{
+  /*= Library ==============================================================*/
+  @supports -moz-bool-pref("userChrome.rounding.square_button") {
+    #placesToolbar > toolbarbutton,
+    #placesMenu > menu,
+    #editBookmarkPanelRows .expander-up,
+    #editBookmarkPanelRows .expander-down {
+      border-radius: 0 !important;
+    }
+  }
+  @supports -moz-bool-pref("userChrome.rounding.square_field") {
+    #searchFilter,
+    #detailsPane html|input,
+    #places input #editBMPanel_tagsSelectorRow > richlistbox {
+      border-radius: 0 !important;
+    }
+  }
+}
 /** Monospace *****************************************************************/
 @supports -moz-bool-pref("userContent.page.monospace") {
   @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/places/places.xhtml"), regexp("^(((jar:)?file:///)|(chrome://)).*/$")
@@ -2778,6 +2933,11 @@
         :root {
           --context-menu-background-padding-default: 2px;
         }
+        @media (-moz-windows-classic) {
+          :root {
+            --context-menu-background-padding-default: -0.5px;
+          }
+        }
       }
       @media (-moz-os-version: windows-win8), (-moz-platform: windows-win8) {
         :root {
@@ -2812,6 +2972,45 @@
             --context-menu-background-padding: 3px;
             --menu-background-padding-default: 0px;
           }
+          @supports -moz-bool-pref("userChrome.compatibility.os.win11") {
+            :root {
+              --context-menu-background-padding: 5px;
+            }
+          }
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic > .menu-iconic-left,
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menuitem-iconic > .menu-iconic-left,
+          menupopup:not([placespopup="true"]) .menu-iconic > .menu-iconic-left,
+          menupopup:not([placespopup="true"]) .menuitem-iconic > .menu-iconic-left {
+            appearance: none !important;
+            padding-block: 0 !important;
+            padding-inline-start: 5px !important;
+            margin-inline-end: 8px !important;
+          }
+          @supports -moz-bool-pref("userChrome.compatibility.os.win11") {
+            menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic > .menu-iconic-left,
+            menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menuitem-iconic > .menu-iconic-left,
+            menupopup:not([placespopup="true"]) .menu-iconic > .menu-iconic-left,
+            menupopup:not([placespopup="true"]) .menuitem-iconic > .menu-iconic-left {
+              box-sizing: content-box;
+            }
+          }
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-accel,
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic-accel,
+          menupopup:not([placespopup="true"]) .menu-accel,
+          menupopup:not([placespopup="true"]) .menu-iconic-accel {
+            box-sizing: content-box;
+            min-height: 16px;
+          }
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-accel,
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic-accel,
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-text,
+          menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) .menu-iconic-text,
+          menupopup:not([placespopup="true"]) .menu-accel,
+          menupopup:not([placespopup="true"]) .menu-iconic-accel,
+          menupopup:not([placespopup="true"]) .menu-text,
+          menupopup:not([placespopup="true"]) .menu-iconic-text {
+            padding-block: 0 !important;
+          }
         }
         menupopup:is(#placesContext, #placesColumnsContext, #downloadsContextMenu)
           menuitem:not(.menuitem-iconic, .bookmark-item, .in-menulist, [checked="true"]),
diff --git a/docs/Preference.md b/docs/Preference.md
index 5c94d1e..6598494 100644
--- a/docs/Preference.md
+++ b/docs/Preference.md
@@ -146,16 +146,32 @@ Customizations that cannot be done with add-on and [`User Custom CSS`](./README.
 - [Bug 1432901 - Prototype loading ES6 Module as JSM](https://bugzilla.mozilla.org/show_bug.cgi?id=1432901)
 
 **How to**
+- `<FIREFOX_DIR>/defaults/pref/autoconfig.js`
 ```javascript
 pref("general.config.filename", "config.js"); // alternative to "firefox.cfg", for using highlight
 pref("general.config.obscure_value", 0);
+pref("general.config.sandbox_enabled", false); // Sandbox needs to be disabled in release and Beta versions
+```
+
+- `<FIREFOX_DIR>/config.js`
+```javascript
+// skip 1st line
+try {
+  const cmanifest = Cc['@mozilla.org/file/directory_service;1'].getService(Ci.nsIProperties).get('UChrm', Ci.nsIFile);
+  cmanifest.append('utils');
+  cmanifest.append('chrome.manifest');
+
+  if(cmanifest.exists()){
+    Components.manager.QueryInterface(Ci.nsIComponentRegistrar).autoRegister(cmanifest);
+    ChromeUtils.import('chrome://userchromejs/content/boot.jsm');
+  }
+
+} catch(ex) {};
 ```
 
 **Example**
-```javascript
-pref("general.config.filename", "config.js"); // alternative to "firefox.cfg", for using highlight
-pref("general.config.obscure_value", 0);
-```
+- [MrOtherGuy/fx-autoconfig](https://github.com/MrOtherGuy/fx-autoconfig)
+- [xiaoxiaoflood/firefox-scripts](https://github.com/xiaoxiaoflood/firefox-scripts)
 
 ## Using with User Custom CSS
 **Related Docs**
diff --git a/src/autohide/_back_button.scss b/src/autohide/_back_button.scss
index 21cc162..d817a08 100644
--- a/src/autohide/_back_button.scss
+++ b/src/autohide/_back_button.scss
@@ -1,4 +1,4 @@
-#back-button[disabled="true"] {
+:root:not([customizing="true"]) #back-button[disabled="true"] {
   margin-left: var(--uc-toolbarbutton-hide-size) !important;
   opacity: 0 !important;
   pointer-events: none;
diff --git a/src/autohide/_forward_button.scss b/src/autohide/_forward_button.scss
index 4e6e240..ddb47b0 100644
--- a/src/autohide/_forward_button.scss
+++ b/src/autohide/_forward_button.scss
@@ -1,4 +1,4 @@
-#forward-button[disabled="true"] {
+ :root:not([customizing="true"]) #forward-button[disabled="true"] {
   margin-left: var(--uc-toolbarbutton-hide-size) !important;
   opacity: 0 !important;
   pointer-events: none;
diff --git a/src/autohide/_index.scss b/src/autohide/_index.scss
index 805c44e..4fcc990 100644
--- a/src/autohide/_index.scss
+++ b/src/autohide/_index.scss
@@ -1,14 +1,17 @@
 @include Option("userChrome.autohide.back_button", "userChrome.autohide.forward_button") {
   :root {
-    --uc-toolbarbutton-hide-size: calc(-1 * (16px + (2 * var(--toolbarbutton-outer-padding) + var(--toolbarbutton-inner-padding))));
+    --uc-toolbarbutton-hide-size: calc(-1 * (16px + (2 * (var(--toolbarbutton-outer-padding) + var(--toolbarbutton-inner-padding)))));
   }
 }
 
-@include Option("userChrome.autohide.back_button") {
-  @import "back_button";
-}
-@include Option("userChrome.autohide.forward_button") {
-  @import "forward_button";
+@include moz-document(url "chrome://browser/content/browser.xhtml")
+{
+  @include Option("userChrome.autohide.back_button") {
+    @import "back_button";
+  }
+  @include Option("userChrome.autohide.forward_button") {
+    @import "forward_button";
+  }
 }
 @include Option("userChrome.autohide.page_action") {
   @import "page_action";
diff --git a/src/compatibility/_os.scss b/src/compatibility/_os.scss
index 64edc40..d5fa112 100644
--- a/src/compatibility/_os.scss
+++ b/src/compatibility/_os.scss
@@ -104,18 +104,20 @@
 //------------------------------------------------------------------------------
 
 @include OS($win7) {
-  @include _os_menuEmulate(5%, 60%);
+  @media (-moz-windows-classic: 0) {
+    @include _os_menuEmulate(5%, 60%);
 
-  /* Remove text shadow */
-  :root:-moz-lwtheme #toolbar-menubar {
-    text-shadow: unset !important;
-    /* Original: 0 0 .5em white, 0 0 .5em white, 0 1px 0 rgba(255, 255, 255, .4) */
-  }
+    /* Remove text shadow */
+    :root:-moz-lwtheme #toolbar-menubar {
+      text-shadow: unset !important;
+      /* Original: 0 0 .5em white, 0 0 .5em white, 0 1px 0 rgba(255, 255, 255, .4) */
+    }
 
-  /* Remove Color */
-  :root:-moz-lwtheme #main-menubar:not(:-moz-window-inactive) {
-    background-color: unset !important; /* Original: rgba(255, 255, 255, .5) */
-    color: unset !important; /* Original: black */
+    /* Remove Color */
+    :root:-moz-lwtheme #main-menubar:not(:-moz-window-inactive) {
+      background-color: unset !important; /* Original: rgba(255, 255, 255, .5) */
+      color: unset !important; /* Original: black */
+    }
   }
 }
 @include OS($win8) {
@@ -125,10 +127,9 @@
 /*= Windows 10 - Native Menu Active Color =====================================*/
 @include OS($win10) {
   @include Win10_NativeMenu() {
-    menu[_moz-menuactive="true"],
-    menuitem[_moz-menuactive="true"] {
-      menupopup:is(#historyMenuPopup, #bookmarksMenuPopup) &,
-      menupopup:not([placespopup="true"]) & {
+    @include NativeMenuPopup {
+      menu[_moz-menuactive="true"],
+      menuitem[_moz-menuactive="true"] {
         background-color: #91c9f7 !important; // color-mix(in srgb, -moz-menuhover 40%, transparent)
         border-color: transparent !important;
 
diff --git a/src/compatibility/_theme.scss b/src/compatibility/_theme.scss
index d46bf5c..331a8a2 100644
--- a/src/compatibility/_theme.scss
+++ b/src/compatibility/_theme.scss
@@ -24,6 +24,13 @@
   }
 }
 
+/*= Subview button, Menu's right padding #597 ================================*/
+.subviewbutton.toolbaritem-combined-buttons:not([shortcut]),
+.subviewbutton.subviewbutton-nav:not([shortcut]),
+menu.subviewbutton {
+  padding-inline-end: 0 !important;
+}
+
 /*= Icon Fill Color ==========================================================*/
 :root:-moz-lwtheme {
   /* Auto create --lwt-toolbarbutton-icon-fill-attention, fix for nightly default theme
diff --git a/src/contents/_rounding.scss b/src/contents/_rounding.scss
new file mode 100644
index 0000000..e7bdde3
--- /dev/null
+++ b/src/contents/_rounding.scss
@@ -0,0 +1,99 @@
+@include Option("userChrome.rounding.square_button") {
+  @include moz-document(url-prefix "about:", url-prefix "chrome://browser/content/preferences/dialogs") {
+    button,
+    .close-icon,
+    .action-icon::before,
+    #categories > .category,
+    .sidebar-footer-link {
+      border-radius: 0 !important;
+    }
+  }
+
+  @include moz-document(url-prefix "about:debugging") {
+    .sidebar-item {
+      border-radius: 0 !important;
+    }
+  }
+
+  @include moz-document(url-prefix "chrome://browser/content/places/places.xhtml", url-prefix "about:downloads") {
+    .downloadButton > .button-box {
+      border-radius: 0 !important;
+    }
+  }
+
+  @include moz-document(url-prefix "about:protections") {
+    #manage-protections,
+    #sign-up-for-monitor-link,
+    #get-proxy-extension-link,
+    #get-vpn-link,
+    #vpn-banner-link,
+    .monitor-partial-breaches-link-wrapper,
+    .monitor-breaches-link-wrapper {
+      border-radius: 0 !important;
+    }
+  }
+}
+
+@include Option("userChrome.rounding.square_dialog") {
+  @include moz-document(url-prefix "about:") {
+    .dialogBox {
+      border-radius: 0 !important;
+    }
+  }
+
+  @include moz-document(url "about:home", url "about:newtab") {
+    .modal {
+      border-radius: 0 !important;
+    }
+  }
+}
+
+@include Option("userChrome.rounding.square_checklabel") {
+  @include moz-document(url-prefix "about:", url-prefix "chrome://browser/content/preferences/dialogs") {
+    input[type="checkbox"]:not(.toggle-button),
+    .checkbox-check {
+      border-radius: 0 !important;
+    }
+  }
+}
+
+@include Option("userChrome.rounding.square_field") {
+  @include moz-document(url-prefix "about:", url-prefix "chrome://browser/content/preferences/dialogs") {
+    input:is([type="email"], [type="tel"], [type="text"], [type="password"], [type="url"], [type="number"]),
+    textarea,
+    select,
+    menulist,
+    search-textbox {
+      border-radius: 0 !important;
+    }
+  }
+
+  @include moz-document(url-prefix "about:debugging") {
+    .default-input {
+      border-radius: 0 !important;
+    }
+  }
+
+  @include moz-document(url "about:home", url "about:newtab") {
+    .search-wrapper {
+      .search-handoff-button,
+      input {
+        border-radius: 0 !important;
+      }
+    }
+  }
+}
+
+@include Option("userChrome.rounding.square_menupopup") {
+  @include moz-document(url-prefix "about:", url-prefix "chrome://") {
+    menupopup {
+      --panel-border-radius: 0 !important;
+    }
+  }
+
+  @include moz-document(url "about:home", url "about:newtab") {
+    .context-menu {
+      border-radius: 0 !important;
+    }
+  }
+}
diff --git a/src/contents/proton_contents/_proton_commons.scss b/src/contents/proton_contents/_proton_commons.scss
index 9be371a..ee2e7b6 100644
--- a/src/contents/proton_contents/_proton_commons.scss
+++ b/src/contents/proton_contents/_proton_commons.scss
@@ -70,6 +70,10 @@
     margin: 4px 8px !important;
     /* Ensure font-size isn't overridden by widget styling (e.g. in forms.css) */
     font-size: 1em !important;
+
+    @include Option("userChrome.rounding.square_button") {
+      border-radius: 0 !important;
+    }
   }
   button {
     font-weight: 600 !important;
@@ -144,6 +148,10 @@
     border-radius: 2px !important;
     margin-inline: 0 6px !important;
     flex-shrink: 0 !important; /* avoid shrinking inside flex container */
+
+    @include Option("userChrome.rounding.square_checklabel") {
+      border-radius: 0 !important;
+    }
   }
   input[type="checkbox"]:enabled:hover {
     background-color: var(--checkbox-unchecked-hover-bgcolor) !important;
diff --git a/src/decoration/_cursor.scss b/src/decoration/_cursor.scss
index 74aec7c..acc4b34 100644
--- a/src/decoration/_cursor.scss
+++ b/src/decoration/_cursor.scss
@@ -23,13 +23,13 @@ menuitem.openintabs-menuitem,
 #identity-popup-clear-sitedata-button,
 #identity-popup-more-info,
 #unified-extensions-manage-extensions,
-.unified-extensions-item-open-menu {
+.unified-extensions-item-open-menu,
+.unified-extensions-item-menu-button.subviewbutton {
   cursor: pointer !important;
 }
 
-/* TODO: For now, fxa-menu doesn't show any status.
-           (JS required, observe .syncNowBtn status)
-  #PanelUI-fxa-menu-syncnow-button[syncstatus="active"] {
-    cursor: progress !important;
-  }
-  */
+// TODO: For now, fxa-menu doesn't show any status.
+//          (JS required, observe .syncNowBtn status)
+// #PanelUI-fxa-menu-syncnow-button[syncstatus="active"] {
+//   cursor: progress !important;
+// }
diff --git a/src/fullscreen/_show_bookmarkbar.css b/src/fullscreen/_show_bookmarkbar.scss
similarity index 100%
rename from src/fullscreen/_show_bookmarkbar.css
rename to src/fullscreen/_show_bookmarkbar.scss
diff --git a/src/hidden/_index.scss b/src/hidden/_index.scss
index 3047a1c..6bfc65d 100644
--- a/src/hidden/_index.scss
+++ b/src/hidden/_index.scss
@@ -65,6 +65,12 @@
       }
     }
     @include Option("userChrome.hidden.urlbar_iconbox.label_only") {
+      &.notSecureText,
+      &.chromeUI,
+      &.extensionPage {
+        margin-inline-end: var(--identity-box-margin-inline) !important;
+      }
+
       &.chromeUI #identity-icon-box,
       &.extensionPage #identity-icon-box {
         &:not(:hover) {
diff --git a/src/icons/_global_menu.scss b/src/icons/_global_menu.scss
index 0c20225..6d1d8ee 100644
--- a/src/icons/_global_menu.scss
+++ b/src/icons/_global_menu.scss
@@ -104,7 +104,8 @@ menu.share-tab-url-item {
   --menuitem-image: url("../icons/toolbar.svg");
 }
 #viewSidebarMenuMenu {
-  --menuitem-image: url("chrome://browser/skin/sidebars.svg");
+  // --menuitem-image: url("chrome://browser/skin/sidebars.svg");
+  --menuitem-image: var(--uc-sidebar-icon);
 }
 
 #viewFullZoomMenu {
diff --git a/src/icons/_index.scss b/src/icons/_index.scss
index ee4a326..f158aa0 100644
--- a/src/icons/_index.scss
+++ b/src/icons/_index.scss
@@ -4,6 +4,16 @@
 }
 
 /** Panel - Icons *************************************************************/
+:root {
+  --uc-sidebar-icon: url("chrome://browser/skin/sidebars.svg");
+  --uc-sidebar-icon-reverse: url("chrome://browser/skin/sidebars-right.svg");
+  @include Has {
+    &:has(#sidebar-box[positionend="true"]) {
+      --uc-sidebar-icon: url("chrome://browser/skin/sidebars-right.svg");
+      --uc-sidebar-icon-reverse: url("chrome://browser/skin/sidebars.svg");
+    }
+  }
+}
 @include Option("userChrome.icon.panel") {
   @import "layout/panel";
   @import "panel";
diff --git a/src/icons/_panel.scss b/src/icons/_panel.scss
index 87511f5..7c310f2 100644
--- a/src/icons/_panel.scss
+++ b/src/icons/_panel.scss
@@ -390,6 +390,10 @@ panelMenuBookmarkThisPage[starred] {
 
 /*= BMB_bookmarksPopup =======================================================*/
 #BMB_viewBookmarksSidebar {
+  --menuitem-image: var(--uc-sidebar-icon);
+  &[data-l10n-args='{"isVisible":true}'] {
+    --menuitem-image: url("chrome://global/skin/icons/close.svg");
+  }
 }
 #BMB_bookmarksShowAllTop,
 #BMB_bookmarksShowAll {
@@ -469,11 +473,7 @@ panelMenuBookmarkThisPage[starred] {
 }
 
 #sidebar-reverse-position {
-  list-style-image: url("chrome://browser/skin/sidebars-right.svg");
-}
-#sidebar-box[positionend="true"] #sidebar-reverse-position {
-  /* Can't apply this. shadow dom */
-  list-style-image: url("chrome://browser/skin/sidebars.svg");
+  list-style-image: var(--uc-sidebar-icon-reverse);
 }
 
 #sidebarMenu-popup > .subviewbutton[data-l10n-id="sidebar-menu-close"] {
diff --git a/src/icons/layout/_bookmark_menu.scss b/src/icons/layout/_bookmark_menu.scss
index 7e3a8a3..78cc127 100644
--- a/src/icons/layout/_bookmark_menu.scss
+++ b/src/icons/layout/_bookmark_menu.scss
@@ -80,9 +80,11 @@ $_bookmarkToolbarMenus: selector.nest(
 @include OS($win10) {
   /* Bookmark Popup - None icon menu */
   @include _layoutBookmarkMenu() {
-    margin-inline: var(--arrowpanel-menuitem-padding-inline) !important;
-    padding-inline-start: calc(var(--arrowpanel-menuicon-padding) + var(--context-menu-text-padding)) !important;
-    background-position: var(--uc-menu-background-position) calc(var(--arrowpanel-menuicon-padding)) center !important;
+    --arrowpanel-bookmark-menuicon-padding: calc(var(--arrowpanel-menuicon-padding) - var(--arrowpanel-menuitem-margin-inline));
+
+    margin-inline-start: var(--arrowpanel-menuitem-margin-inline) !important;
+    padding-inline-start: calc(var(--arrowpanel-bookmark-menuicon-padding) + var(--context-menu-text-padding)) !important;
+    background-position: var(--uc-menu-background-position) var(--arrowpanel-bookmark-menuicon-padding) center !important;
   }
 }
 
diff --git a/src/icons/layout/_menu_common.scss b/src/icons/layout/_menu_common.scss
index 62a3f35..eb3af6c 100644
--- a/src/icons/layout/_menu_common.scss
+++ b/src/icons/layout/_menu_common.scss
@@ -79,6 +79,9 @@ $_initialMenus: selector.append(
   @include OS($win7) {
     :root {
       --context-menu-background-padding-default: 2px;
+      @media (-moz-windows-classic) {
+        --context-menu-background-padding-default: -0.5px;
+      }
     }
   }
   @include OS($win8) {
@@ -97,10 +100,37 @@ $_initialMenus: selector.append(
     --context-menu-background-padding: 1em;
     --context-menu-text-padding: 24px; /* 16px + 8px */
     --menu-background-padding-default: calc(var(--context-menu-background-padding) + var(--context-menu-text-padding));
-
-    @include Win10_NativeMenu() {
+  }
+  @include Win10_NativeMenu() {
+    :root {
       --context-menu-background-padding: 3px;
       --menu-background-padding-default: 0px;
+      @include Option("userChrome.compatibility.os.win11") {
+        --context-menu-background-padding: 5px;
+      }
+    }
+
+    @include NativeMenuPopup {
+      .menu-iconic,
+      .menuitem-iconic {
+        > .menu-iconic-left {
+          appearance: none !important;
+          padding-block: 0 !important;
+          padding-inline-start: 5px !important;
+          margin-inline-end: 8px !important;
+          @include Option("userChrome.compatibility.os.win11") {
+            box-sizing: content-box;
+          }
+        }
+      }
+      .menu-accel, .menu-iconic-accel {
+        box-sizing: content-box;
+        min-height: 16px;
+      }
+      .menu-accel, .menu-iconic-accel,
+      .menu-text, .menu-iconic-text {
+        padding-block: 0 !important;
+      }
     }
   }
 }
diff --git a/src/leptonContent.scss b/src/leptonContent.scss
index 2242f48..abe1704 100644
--- a/src/leptonContent.scss
+++ b/src/leptonContent.scss
@@ -35,6 +35,14 @@
   @import "contents/proton_contents";
 }
 
+/** Rounding ******************************************************************/
+@import "contents/rounding";
+
+// Put here to include library as a tab
+@include moz-document(url "chrome://browser/content/places/places.xhtml") {
+  @import "rounding/library";
+}
+
 /** Monospace *****************************************************************/
 @include Option("userContent.page.monospace") {
   @import "contents/monospace";
diff --git a/src/library/_proton.scss b/src/library/_proton.scss
index 8a1d961..f48a152 100644
--- a/src/library/_proton.scss
+++ b/src/library/_proton.scss
@@ -82,6 +82,10 @@
     padding: 5px !important;
     border-radius: 4px !important;
 
+    @include Option("userChrome.rounding.square_button") {
+      border-radius: 0 !important;
+    }
+
     &[disabled] {
       opacity: 0.6 !important;
     }
@@ -108,11 +112,15 @@
   > menu {
     appearance: none !important;
     color: var(--organizer-color) !important;
-    border-radius: 4px !important;
     padding-block: 5px !important;
     padding-inline-start: 5px !important;
+    border-radius: 4px !important;
     margin-inline-end: 2px !important;
 
+    @include Option("userChrome.rounding.square_button") {
+      border-radius: 0 !important;
+    }
+
     &[_moz-menuactive="true"],
     &:hover {
       background-color: var(--organizer-hover-background) !important;
@@ -141,6 +149,10 @@
   margin: 0 !important;
   padding-block: 2px !important;
   min-height: 24px !important;
+
+  @include Option("userChrome.rounding.square_field") {
+    border-radius: 0 !important;
+  }
 }
 
 #searchFilter[focused] {
@@ -304,6 +316,10 @@ treechildren {
   -moz-context-properties: fill !important;
   fill: currentColor !important;
 
+  @include Option("userChrome.rounding.square_button") {
+    border-radius: 0 !important;
+  }
+
   &:hover {
     background-color: var(--organizer-hover-background) !important;
     color: var(--organizer-hover-color) !important;
@@ -340,6 +356,10 @@ treechildren {
   min-height: 20px !important;
   padding-inline: 4px !important;
 
+  @include Option("userChrome.rounding.square_field") {
+    border-radius: 0 !important;
+  }
+
   &:focus {
     outline: 2px solid var(--organizer-outline-color) !important;
     outline-offset: -1px !important;
@@ -361,6 +381,10 @@ treechildren {
   border: 1px solid var(--organizer-border-color) !important;
   border-radius: 4px !important;
 
+  @include Option("userChrome.rounding.square_field") {
+    border-radius: 0 !important;
+  }
+
   > richlistitem {
     border: 1px solid transparent !important;
 
diff --git a/src/padding/_panel.scss b/src/padding/_panel.scss
index 8d1fde8..716d2c4 100644
--- a/src/padding/_panel.scss
+++ b/src/padding/_panel.scss
@@ -1,5 +1,7 @@
 :root {
-  --arrowpanel-menuitem-margin: 0 var(--arrowpanel-menuicon-padding, 8px) !important; /* Original: 0 8px */
+  --arrowpanel-menuitem-margin-block: 0; /* FF 102 compatibility */
+  --arrowpanel-menuitem-margin-inline: 8px;
+  --arrowpanel-menuitem-margin: var(--arrowpanel-menuitem-margin-block) var(--arrowpanel-menuitem-margin-inline) !important; /* Original: 0 8px */
   --arrowpanel-menuitem-padding-block: 5px !important; /* Original: 8px */
   --arrowpanel-menuitem-padding-inline: 5px !important; /* Original: 8px */
   --arrowpanel-menuitem-padding: var(--arrowpanel-menuitem-padding-block) var(--arrowpanel-menuitem-padding-inline) !important; /* Compatibility */
@@ -7,6 +9,7 @@
 }
 
 :root[uidensity="compact"] {
+  --arrowpanel-menuitem-margin-inline: 4px; /* FF 102 compatibility */
   --arrowpanel-menuitem-padding-block: 3px !important;
   --arrowpanel-menuitem-padding-inline: 3px !important;
 }
@@ -15,6 +18,10 @@
   --arrowpanel-menuitem-padding-inline: 8px !important; /* Original: 8px */
 }
 
+.all-tabs-item {
+  margin: var(--arrowpanel-menuitem-margin) !important;
+}
+
 @include NotOption("userChrome.icon.disabled") {
   @include NotOption("userChrome.icon.panel") {
     .subviewbutton {
@@ -22,3 +29,12 @@
     }
   }
 }
+
+// #603
+.unified-extensions-item-menu-button.subviewbutton {
+  padding: 8px !important; /* Original: var(--arrowpanel-menuitem-padding-inline) */
+}
+// Or
+// toolbaritem.unified-extensions-item[unified-extensions="true"] .unified-extensions-item-menu-button.subviewbutton {
+//   padding: var(--arrowpanel-menuitem-padding-inline) !important;
+// }
diff --git a/src/rounding/_index.scss b/src/rounding/_index.scss
index a46fa88..577efc6 100644
--- a/src/rounding/_index.scss
+++ b/src/rounding/_index.scss
@@ -1,5 +1,6 @@
 /** Rounding ******************************************************************/
 @import "square";
+@import "library";
 
 /*
 --toolbarbutton-border-radius: 4px;
diff --git a/src/rounding/_library.scss b/src/rounding/_library.scss
new file mode 100644
index 0000000..a31bc2e
--- /dev/null
+++ b/src/rounding/_library.scss
@@ -0,0 +1,17 @@
+/*= Library ==============================================================*/
+@include Option("userChrome.rounding.square_button") {
+  #placesToolbar > toolbarbutton,
+  #placesMenu > menu,
+  #editBookmarkPanelRows .expander-up,
+  #editBookmarkPanelRows .expander-down {
+    border-radius: 0 !important;
+  }
+}
+@include Option("userChrome.rounding.square_field") {
+  #searchFilter,
+  #detailsPane html|input,
+  #places input
+  #editBMPanel_tagsSelectorRow > richlistbox {
+    border-radius: 0 !important;
+  }
+}
diff --git a/src/rounding/_square.scss b/src/rounding/_square.scss
index 9c86f15..d2dd19e 100644
--- a/src/rounding/_square.scss
+++ b/src/rounding/_square.scss
@@ -15,6 +15,7 @@
   .urlbarView-button,
   .urlbarView-tip-button,
   .urlbarView-action,
+  .tab-close-button,
   toolbarbutton.bookmark-item:not(.subviewbutton),
   #sidebar-switcher-target {
     --toolbarbutton-border-radius: 0;  /* Original: 4px */
@@ -22,7 +23,8 @@
 
   button,
   findbar toolbarbutton,
-  .notification-button {
+  .notification-button,
+  #main-menubar > menu {
     border-radius: 0 !important;
   }
 }
@@ -34,6 +36,12 @@
   }
 }
 
+@include Option("userChrome.rounding.square_dialog") {
+  .dialogBox {
+    border-radius: 0 !important;
+  }
+}
+
 @include Option("userChrome.rounding.square_panel") {
   :root {
     --arrowpanel-border-radius: 0 !important;
@@ -47,7 +55,7 @@
 }
 
 @include Option("userChrome.rounding.square_menupopup") {
-  xul|menupopup {
+  menupopup {
     --panel-border-radius: 0px !important;
     border-radius: 0 !important;
   }
@@ -64,6 +72,7 @@
   html|select[size][multiple],
   xul|listheader,
   xul|richlistbox,
+  xul|menulist,
   html|input {
     border-radius: 0 !important;
   }
@@ -82,8 +91,7 @@
 }
 
 @include Option("userChrome.rounding.square_checklabel") {
-  .checkbox-check,
-  xul|*.radio-check {
+  .checkbox-check {
     border-radius: 0 !important;
   }
 }
diff --git a/src/theme/proton_chrome/_page_info.scss b/src/theme/proton_chrome/_page_info.scss
index 26b5bc6..7e7624d 100644
--- a/src/theme/proton_chrome/_page_info.scss
+++ b/src/theme/proton_chrome/_page_info.scss
@@ -5,7 +5,6 @@
   }
 
   #viewGroup > radio {
-    border-radius: 8px !important;
     padding: var(--in-content-button-vertical-padding) var(--in-content-button-horizontal-padding) !important;
     margin: 4px !important;
 
@@ -18,6 +17,11 @@
     -moz-context-properties: fill !important;
     fill: currentColor !important;
     color: var(--in-content-deemphasized-text) !important; /* FieldText */
+
+    @include NotOption("userChrome.rounding.square_button") {
+      border-radius: 8px !important;
+    }
+
     &:hover {
       background-color: var(--in-content-button-background-hover) !important; /* #E0E8F6; */
     }
diff --git a/src/utils/_native_menu.scss b/src/utils/_native_menu.scss
index aeb7969..66ac8ce 100644
--- a/src/utils/_native_menu.scss
+++ b/src/utils/_native_menu.scss
@@ -6,6 +6,13 @@
   }
 }
 
+@mixin NativeMenuPopup() {
+  menupopup:is(#historyMenuPopup, #bookmarksMenuPopup),
+  menupopup:not([placespopup="true"]) {
+    @content;
+  }
+}
+
 @mixin Win10_NativeMenu() {
   @media not (-moz-windows-non-native-menus) {
     @content;
diff --git a/user.js b/user.js
index 5b3e808..26cbcee 100644
--- a/user.js
+++ b/user.js
@@ -70,6 +70,7 @@ user_pref("userChrome.rounding.square_tab",           false);
 // -- User Chrome --------------------------------------------------------------
 // user_pref("userChrome.theme.proton_color.dark_blue_accent", true);
 // user_pref("userChrome.theme.monospace",                     true);
+// user_pref("userChrome.compatibility.os.win11",              true);
 
 // user_pref("userChrome.decoration.disable_panel_animate",    true);
 // user_pref("userChrome.decoration.disable_sidebar_animate",  true);
@@ -120,6 +121,7 @@ user_pref("userChrome.rounding.square_tab",           false);
 // user_pref("userChrome.combined.sub_button.as_normal",       true);
 
 // user_pref("userChrome.rounding.square_button",              true);
+// user_pref("userChrome.rounding.square_dialog",              true);
 // user_pref("userChrome.rounding.square_panel",               true);
 // user_pref("userChrome.rounding.square_panelitem",           true);
 // user_pref("userChrome.rounding.square_menupopup",           true);