--- a/browser/base/content/browser.css
+++ b/browser/base/content/browser.css
@@ -133,26 +133,16 @@ tabbrowser {
 #TabsToolbar[customizing="true"] > #tabbrowser-tabs > .tabbrowser-arrowscrollbox > .tabs-newtab-button {
   visibility: collapse;
 }
 
 #tabbrowser-tabs:not([overflow="true"])[using-closing-tabs-spacer] ~ #alltabs-button {
   visibility: hidden; /* temporary space to keep a tab's close button under the cursor */
 }
 
-.tabs-newtab-button > .toolbarbutton-menu-dropmarker,
-#new-tab-button > .toolbarbutton-menu-dropmarker {
-  display: none;
-}
-
-/* override drop marker image padding */
-.tabs-newtab-button > .toolbarbutton-icon {
-  margin-inline-end: 0;
-}
-
 .tabbrowser-tab {
   -moz-binding: url("chrome://browser/content/tabbrowser.xml#tabbrowser-tab");
 }
 
 .tabbrowser-tab:not([pinned]) {
   -moz-box-flex: 100;
   max-width: 210px;
   min-width: 100px;

--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -1050,20 +1050,16 @@ html|span.ac-emphasize-text-url {
   list-style-image: url("chrome://browser/skin/tabbrowser/alltabs.png");
 }
 
 #TabsToolbar[brighttext] > #alltabs-button,
 #TabsToolbar[brighttext] > toolbarpaletteitem > #alltabs-button {
   list-style-image: url("chrome://browser/skin/tabbrowser/alltabs-inverted.png");
 }
 
-#alltabs-button > .toolbarbutton-menu-dropmarker {
-  display: none;
-}
-
 /* All tabs menupopup */
 .alltabs-item > .menu-iconic-left > .menu-iconic-icon {
   list-style-image: url("chrome://mozapps/skin/places/defaultFavicon.svg");
 }
 
 .alltabs-item[selected="true"] {
   font-weight: bold;
 }

--- a/browser/themes/osx/browser.css
+++ b/browser/themes/osx/browser.css
@@ -1781,20 +1781,16 @@ toolbarbutton.chevron > .toolbarbutton-m
     -moz-image-region: rect(0, 102px, 40px, 68px);
   }
 
   #alltabs-button > .toolbarbutton-icon {
     width: 17px;
   }
 }
 
-#alltabs-button > .toolbarbutton-menu-dropmarker {
-  display: none;
-}
-
 /* All Tabs Menupopup */
 .alltabs-item > .menu-iconic-left > .menu-iconic-icon {
   list-style-image: url("chrome://mozapps/skin/places/defaultFavicon.svg");
 }
 
 .alltabs-item[busy] > .menu-iconic-left > .menu-iconic-icon {
   list-style-image: url("chrome://global/skin/icons/loading.png") !important;
 }

--- a/browser/themes/shared/tabs.inc.css
+++ b/browser/themes/shared/tabs.inc.css
@@ -521,16 +521,25 @@
 }
 
 /* New tab button */
 
 .tabs-newtab-button {
   width: calc(36px + var(--tab-curve-width));
 }
 
+.tabs-newtab-button > .toolbarbutton-menu-dropmarker {
+  display: none;
+}
+
+.tabs-newtab-button > .toolbarbutton-icon {
+  /* override drop marker image padding */
+  margin-inline-end: 0;
+}
+
 @media (min-resolution: 1.1dppx) {
   /* image preloading hack from like lowdpi styles */
   #tabbrowser-tabs::before {
     background-image:
       url(chrome://browser/skin/tabbrowser/tab-background-end@2x.png),
       url(chrome://browser/skin/tabbrowser/tab-background-middle@2x.png),
       url(chrome://browser/skin/tabbrowser/tab-background-start@2x.png);
   }

--- a/browser/themes/shared/toolbarbuttons.inc.css
+++ b/browser/themes/shared/toolbarbuttons.inc.css
@@ -56,29 +56,26 @@ toolbar[brighttext] {
 /* ::::: primary toolbar buttons ::::: */
 
 .tabbrowser-arrowscrollbox > .scrollbutton-up[disabled=true],
 .tabbrowser-arrowscrollbox > .scrollbutton-down[disabled=true],
 /* specialcase the overflow and the hamburger button so they show up disabled in customize mode. */
 #nav-bar-overflow-button[disabled=true] > .toolbarbutton-icon,
 #PanelUI-menu-button[disabled=true] > .toolbarbutton-badge-stack > .toolbarbutton-icon,
 #main-window:not([customizing]) .toolbarbutton-1[disabled=true] > .toolbarbutton-icon,
-#main-window:not([customizing]) .toolbarbutton-1[disabled=true] > .toolbarbutton-menu-dropmarker,
 #main-window:not([customizing]) .toolbarbutton-1[disabled=true] > .toolbarbutton-menubutton-dropmarker,
 #main-window:not([customizing]) .toolbarbutton-1 > .toolbarbutton-menubutton-button[disabled=true] > .toolbarbutton-icon,
 #main-window:not([customizing]) .toolbarbutton-1[disabled=true] > :-moz-any(.toolbarbutton-menubutton-button, .toolbarbutton-badge-stack) > .toolbarbutton-icon {
   opacity: 0.4;
 }
 
-.toolbarbutton-1 > .toolbarbutton-menu-dropmarker,
 .toolbarbutton-1 > .toolbarbutton-menubutton-dropmarker {
   list-style-image: url("chrome://browser/skin/toolbarbutton-dropdown-arrow.png");
 }
 
-toolbar[brighttext] .toolbarbutton-1 > .toolbarbutton-menu-dropmarker,
 toolbar[brighttext] .toolbarbutton-1 > .toolbarbutton-menubutton-dropmarker {
   list-style-image: url("chrome://browser/skin/toolbarbutton-dropdown-arrow-inverted.png");
 }
 
 .toolbarbutton-1 > .toolbarbutton-icon,
 .toolbarbutton-1 > .toolbarbutton-menubutton-button > .toolbarbutton-icon {
   margin-inline-end: 0;
 }
@@ -204,16 +201,18 @@ toolbarbutton.bookmark-item:not(.subview
   border-top-left-radius: 0;
   border-bottom-left-radius: 0;
 }
 
 #nav-bar .toolbarbutton-1 > .toolbarbutton-menubutton-button > .toolbarbutton-icon {
   border-inline-end-style: none;
 }
 
+.bookmark-item > .toolbarbutton-menu-dropmarker,
+#TabsToolbar .toolbarbutton-1 > .toolbarbutton-menu-dropmarker,
 #nav-bar .toolbarbutton-1 > .toolbarbutton-menu-dropmarker {
   display: none;
 }
 
 %ifndef MOZ_PHOTON_THEME
 #nav-bar #bookmarks-menu-button[cui-areatype="toolbar"] > .toolbarbutton-menubutton-button > .toolbarbutton-icon {
   /* horizontal padding + border + actual icon width */
   max-width: 31px;
@@ -459,11 +458,8 @@ toolbarbutton.bookmark-item:not(.subview
 #personal-bookmarks[cui-areatype="toolbar"] > #bookmarks-toolbar-placeholder > .toolbarbutton-text {
   display: -moz-box !important;
 }
 
 .bookmark-item > .toolbarbutton-icon[label]:not([label=""]) {
   margin-inline-end: 5px;
 }
 
-.bookmark-item > .toolbarbutton-menu-dropmarker {
-  display: none;
-}

--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -1500,20 +1500,16 @@ treechildren.searchbar-treebody::-moz-tr
   list-style-image: url("chrome://browser/skin/toolbarbutton-dropdown-arrow.png");
 }
 
 #TabsToolbar[brighttext] > #alltabs-button,
 #TabsToolbar[brighttext] > toolbarpaletteitem > #alltabs-button {
   list-style-image: url("chrome://browser/skin/toolbarbutton-dropdown-arrow-inverted.png");
 }
 
-#alltabs-button > .toolbarbutton-menu-dropmarker {
-  display: none;
-}
-
 /* All tabs menupopup */
 .alltabs-item > .menu-iconic-left > .menu-iconic-icon {
   list-style-image: url("chrome://mozapps/skin/places/defaultFavicon.svg");
 }
 
 .alltabs-item[selected="true"] {
   font-weight: bold;
 }