diff --git a/css/leptonChrome.css b/css/leptonChrome.css
index 72006e4..6d765f8 100644
--- a/css/leptonChrome.css
+++ b/css/leptonChrome.css
@@ -6763,6 +6763,7 @@
 /*= New tab button - Smaller button ==========================================*/
 @supports -moz-bool-pref("userChrome.tab.newtab_button_smaller") {
   #tabs-newtab-button > .toolbarbutton-icon {
+    --tab-border-radius: var(--toolbarbutton-border-radius);
     margin-left: 1px;
     /* Original: calc((var(--tab-min-height) - 16px) / 2) = 10px */
     --toolbarbutton-inner-padding: 6px;
diff --git a/src/tab/newtab_button/_smaller_button.scss b/src/tab/newtab_button/_smaller_button.scss
index f7ab49c..2d82a83 100644
--- a/src/tab/newtab_button/_smaller_button.scss
+++ b/src/tab/newtab_button/_smaller_button.scss
@@ -1,4 +1,6 @@
 #tabs-newtab-button > .toolbarbutton-icon {
+  // Not like tab, as button
+  --tab-border-radius: var(--toolbarbutton-border-radius);
   margin-left: 1px;
 
   /* Original: calc((var(--tab-min-height) - 16px) / 2) = 10px */