diff --git a/css/leptonChrome.css b/css/leptonChrome.css
index 0452a906..768ace0a 100644
--- a/css/leptonChrome.css
+++ b/css/leptonChrome.css
@@ -11605,6 +11605,9 @@
         padding-inline-start: var(--menu-background-padding-default) !important;
         margin-left: 0 !important;
       }
+      .menupopup-arrowscrollbox {
+        padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
+      }
     }
     @media (-moz-platform: windows), (-moz-gtk-csd-available) {
       @supports -moz-bool-pref("userChrome.theme.non_native_menu") {
@@ -11670,6 +11673,9 @@
             padding-inline-start: var(--menu-background-padding-default) !important;
             margin-left: 0 !important;
           }
+          .menupopup-arrowscrollbox {
+            padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
+          }
         }
       }
     }
@@ -26174,6 +26180,9 @@
     padding-inline-start: var(--menu-background-padding-default) !important;
     margin-left: 0 !important;
   }
+  .menupopup-arrowscrollbox {
+    padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
+  }
 }
 @media (not (-moz-bool-pref: "userChrome.icon.disabled")) and (-moz-bool-pref: "userChrome.icon.menu") and (-moz-platform: windows) and (-moz-bool-pref: "userChrome.theme.non_native_menu") and (-moz-gtk-csd-available),
   (not (-moz-bool-pref: "userChrome.icon.disabled")) and (-moz-bool-pref: "userChrome.icon.menu") and (-moz-gtk-csd-available) and (-moz-bool-pref: "userChrome.theme.non_native_menu") and (-moz-gtk-csd-available) {
@@ -26234,6 +26243,9 @@
     padding-inline-start: var(--menu-background-padding-default) !important;
     margin-left: 0 !important;
   }
+  .menupopup-arrowscrollbox {
+    padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
+  }
 }
 @media (not (-moz-bool-pref: "userChrome.icon.disabled")) and (-moz-bool-pref: "userChrome.icon.menu") and (-moz-platform: windows) {
   :root {
diff --git a/css/leptonChromeESR.css b/css/leptonChromeESR.css
index e832e15a..01d509da 100644
--- a/css/leptonChromeESR.css
+++ b/css/leptonChromeESR.css
@@ -12025,6 +12025,9 @@
         padding-inline-start: var(--menu-background-padding-default) !important;
         margin-left: 0 !important;
       }
+      .menupopup-arrowscrollbox {
+        padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
+      }
     }
     @media (-moz-os-version: windows-win7),
       (-moz-os-version: windows-win8),
@@ -12097,6 +12100,9 @@
             padding-inline-start: var(--menu-background-padding-default) !important;
             margin-left: 0 !important;
           }
+          .menupopup-arrowscrollbox {
+            padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
+          }
         }
       }
     }
diff --git a/src/icons/layout/_menu.scss b/src/icons/layout/_menu.scss
index 03e3bf4d..b94e82f5 100644
--- a/src/icons/layout/_menu.scss
+++ b/src/icons/layout/_menu.scss
@@ -94,6 +94,11 @@ $_layoutCommonMenus: (
     @include _layoutIconMenus {
       @include _layout_init_non_native();
     }
+
+    // FF v121
+    .menupopup-arrowscrollbox {
+      padding-inline: 0 !important; /* Original: padding: var(--panel-padding); --panel-padding-block: 4px; */
+    }
   }
 }