diff --git a/docs/Restrictions.md b/docs/Restrictions.md
index 0d82e0f..6da0db3 100644
--- a/docs/Restrictions.md
+++ b/docs/Restrictions.md
@@ -58,6 +58,7 @@ The following code will cause extension panels fail to open and trying to open t
   display: flex;
 }
 ```
+Info: `#nav-bar` is [`toolbar`](https://udn.realityripple.com/docs/Archive/Mozilla/XUL/toolbar).
 
 ## Internals
 ### CSS Loading Order
@@ -108,7 +109,8 @@ Onething bypass method is to declare [`var()`](https://developer.mozilla.org/en-
 - [Video Player Twoline UI](https://github.com/black7375/Firefox-UI-Fix/blob/cbf14cd55a9edada7ab2f5f1b626608fb9fe38a2/src/contents/_video_player.scss#L68-L171): It is pretty difficult when the condition becomes complicated.
 
 ### XUL
-Sometimes firefox can use [XUL](https://en.wikipedia.org/wiki/XUL) that have been written and binded with C++ for performance like a treeview of bookmarks.
+Sometimes firefox can use [XUL](https://en.wikipedia.org/wiki/XUL) that have been written and binded with C++ for performance like a treeview of bookmarks.  
+XUL's [box model](https://udn.realityripple.com/docs/Archive/Mozilla/XUL/Tutorial/The_Box_Model) and [DOM](https://udn.realityripple.com/docs/Archive/Mozilla/XUL/Tutorial/Document_Object_Model) are different from HTML.
 
 There ar few appropriate documents, so we have to read the source code and work. (Ex. [1](https://github.com/mozilla/gecko-dev/blob/master/layout/style/nsCSSAnonBoxList.h), [2](https://github.com/mozilla/gecko-dev/blob/master/layout/xul/tree/nsITreeView.idl))
 
@@ -117,3 +119,6 @@ Available CSS features are also restricted.
 Example of legacy documents that will help.
 - [UDN: ::-moz-tree-cell](https://udn.realityripple.com/docs/Mozilla/Gecko/Chrome/CSS/::-moz-tree-cell)
 - [UDN: ::-moz-tree-cell-text](https://udn.realityripple.com/docs/Mozilla/Gecko/Chrome/CSS/::-moz-tree-cell-text)
+
+Another case.  
+Like [`<toolbar align="end"></toolbar>`](https://udn.realityripple.com/docs/Archive/Mozilla/XUL/Attribute/align), [`attributes`] is set and CSS of same property may not be appplied. (Ex. [`box-align: start`](https://udn.realityripple.com/docs/Web/CSS/box-align))
diff --git a/src/compatibility/_os.scss b/src/compatibility/_os.scss
index 416a4bd..16d0606 100644
--- a/src/compatibility/_os.scss
+++ b/src/compatibility/_os.scss
@@ -121,19 +121,21 @@
   }
 
   /*= Linux - Titlebar button at lwtheme =====================================*/
-  .titlebar-button:-moz-lwtheme {
-    appearance: auto !important;
-  }
-  .titlebar-min:-moz-lwtheme,
-  .titlebar-max:-moz-lwtheme,
-  .titlebar-restore:-moz-lwtheme,
-  .titlebar-close:-moz-lwtheme {
-    list-style-image: none !important;
-  }
-  .titlebar-button:-moz-lwtheme:hover,
-  .titlebar-button:-moz-lwtheme:hover:active {
-    background-color: unset !important;
-    color: unset !important;
+  @include NotOption("userChrome.compatiblity.os.linux_non_native_titlebar_button") {
+    .titlebar-button:-moz-lwtheme {
+      appearance: auto !important;
+    }
+    .titlebar-min:-moz-lwtheme,
+    .titlebar-max:-moz-lwtheme,
+    .titlebar-restore:-moz-lwtheme,
+    .titlebar-close:-moz-lwtheme {
+      list-style-image: none !important;
+    }
+    .titlebar-button:-moz-lwtheme:hover,
+    .titlebar-button:-moz-lwtheme:hover:active {
+      background-color: unset !important;
+      color: unset !important;
+    }
   }
 }
 
diff --git a/src/tabbar/selected_tab/_color_like_toolbar.scss b/src/tabbar/selected_tab/_color_like_toolbar.scss
index 4fc84ca..2495025 100644
--- a/src/tabbar/selected_tab/_color_like_toolbar.scss
+++ b/src/tabbar/selected_tab/_color_like_toolbar.scss
@@ -1,6 +1,7 @@
 :root:not(:-moz-lwtheme) {
-  /* Fix for windows's system default theme. Using --toolbar-bgcolor fallback */
+  /* Fix for windows's system default theme. Using --toolbar-bgcolor, --toolbar-bgimage fallback */
   --tab-selected-bgcolor: unset !important; /* Original: rgb(255,255,255); */
+  --tab-selected-bgimage: unset !important; /* Above FF v101 */
 }
 #tabbrowser-tabs:not([movingtab])
   > #tabbrowser-arrowscrollbox
diff --git a/user.js b/user.js
index 7d2c08e..1c996ef 100644
--- a/user.js
+++ b/user.js
@@ -59,6 +59,8 @@ user_pref("userChrome.tab.bottom_rounded_corner",      true);
 // user_pref("userChrome.compatibility.navbar_top_border",    true);
 // user_pref("userChrome.compatibility.dynamic_separator",    true); // Need dynamic_seperator
 
+// user_pref("userChrome.compatiblity.os.linux_non_native_titlebar_button", true);
+
 // == Theme Custom Settings ====================================================
 // -- User Chrome --------------------------------------------------------------
 // user_pref("userChrome.decoration.disable_panel_animate",    true);
diff --git a/userChrome.css b/userChrome.css
index bdab54c..b1cbef2 100644
--- a/userChrome.css
+++ b/userChrome.css
@@ -273,21 +273,23 @@
     }
 
     /*= Linux - Titlebar button at lwtheme =====================================*/
-    .titlebar-button:-moz-lwtheme {
-      appearance: auto !important;
-    }
+    @supports not -moz-bool-pref("userChrome.compatiblity.os.linux_non_native_titlebar_button") {
+      .titlebar-button:-moz-lwtheme {
+        appearance: auto !important;
+      }
 
-    .titlebar-min:-moz-lwtheme,
-    .titlebar-max:-moz-lwtheme,
-    .titlebar-restore:-moz-lwtheme,
-    .titlebar-close:-moz-lwtheme {
-      list-style-image: none !important;
-    }
+      .titlebar-min:-moz-lwtheme,
+      .titlebar-max:-moz-lwtheme,
+      .titlebar-restore:-moz-lwtheme,
+      .titlebar-close:-moz-lwtheme {
+        list-style-image: none !important;
+      }
 
-    .titlebar-button:-moz-lwtheme:hover,
-    .titlebar-button:-moz-lwtheme:hover:active {
-      background-color: unset !important;
-      color: unset !important;
+      .titlebar-button:-moz-lwtheme:hover,
+      .titlebar-button:-moz-lwtheme:hover:active {
+        background-color: unset !important;
+        color: unset !important;
+      }
     }
   }
   /*= Linux - Light System Default Theme's Selected Tab ========================*/
@@ -3959,9 +3961,11 @@
 /*= Selected Tab - Color like toolbar ========================================*/
 @supports -moz-bool-pref("userChrome.tab.color_like_toolbar") {
   :root:not(:-moz-lwtheme) {
-    /* Fix for windows's system default theme. Using --toolbar-bgcolor fallback */
+    /* Fix for windows's system default theme. Using --toolbar-bgcolor, --toolbar-bgimage fallback */
     --tab-selected-bgcolor: unset !important;
     /* Original: rgb(255,255,255); */
+    --tab-selected-bgimage: unset !important;
+    /* Nightly 101 */
   }
 
   #tabbrowser-tabs:not([movingtab])