--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -741,17 +741,17 @@ toolbar[brighttext] .toolbarbutton-1 > .
 #nav-bar .toolbarbutton-1[type=panel] > .toolbarbutton-badge-stack,
 #nav-bar .toolbarbutton-1[type=menu]:not(#PanelUI-menu-button):not(#back-button):not(#forward-button):not(#new-tab-button) > .toolbarbutton-icon,
 #nav-bar .toolbarbutton-1[type=menu]:not(#PanelUI-menu-button) > .toolbarbutton-badge-stack,
 #nav-bar .toolbarbutton-1[type=menu] > .toolbarbutton-text /* hack for add-ons that forcefully display the label */ {
   padding-inline-end: 17px;
 }
 
 #nav-bar .toolbarbutton-1[type=panel] > .toolbarbutton-icon,
-#nav-bar .toolbarbutton-1[type=menu]:not(#PanelUI-menu-button):not(#back-button):not(#forward-button) > .toolbarbutton-icon {
+#nav-bar .toolbarbutton-1[type=menu]:not(#PanelUI-menu-button):not(#back-button):not(#forward-button):not(#new-tab-button) > .toolbarbutton-icon {
   /* horizontal padding + border + icon width */
   max-width: 43px;
 }
 
 #nav-bar .toolbarbutton-1 > .toolbarbutton-menu-dropmarker {
   margin-inline-start: -15px;
 }