diff --git a/browser/themes/windows/customizableui/panelUI.css b/browser/themes/windows/customizableui/panelUI.css
index 2eb4775aa10e..d412d3011b20 100644
--- a/browser/themes/windows/customizableui/panelUI.css
+++ b/browser/themes/windows/customizableui/panelUI.css
@@ -10,7 +10,3 @@ menupopup::part(drop-indicator) {
   /* To account for the shadow margin + border of the panel */
   margin-inline-start: 5px;
 }
-
-.toolbar-menupopup {
-  --nested-margin: calc(-1 * (var(--arrowpanel-menuitem-padding-inline) + var(--panel-shadow-margin)));
-}
diff --git a/toolkit/themes/linux/global/menu.css b/toolkit/themes/linux/global/menu.css
index 576e7ff78ed6..c6407ac0dc04 100644
--- a/toolkit/themes/linux/global/menu.css
+++ b/toolkit/themes/linux/global/menu.css
@@ -23,9 +23,9 @@ menucaption {
   border-radius: calc(var(--panel-border-radius) / 2);
   align-items: center;
   flex-shrink: 0;
+  list-style-image: none;
   padding: 4px 6px;
   max-width: 42em;
-  list-style-image: none;
 }
 
 menu:where([_moz-menuactive]:not([disabled="true"])),
diff --git a/toolkit/themes/shared/popup.css b/toolkit/themes/shared/popup.css
index 585c4989e905..1cd7fc14e49a 100644
--- a/toolkit/themes/shared/popup.css
+++ b/toolkit/themes/shared/popup.css
@@ -35,7 +35,6 @@ panel {
   @media (-moz-platform: windows) {
     --panel-border-radius: 4px;
     --panel-padding-block: 4px;
-    --nested-margin: -10px;
   }
 
   @media (-moz-platform: linux) or (-moz-platform: windows) {
@@ -103,7 +102,7 @@ panel {
   }
 }
 
-@media (-moz-platform: linux) {
+@media (-moz-platform: linux) or (-moz-platform: windows) {
   menupopup {
     /* Also apply the padding in the inline axis for menus */
     --panel-padding: var(--panel-padding-block);
@@ -129,11 +128,6 @@ panel {
     padding-block: 0.5em;
     padding-inline-start: 1em;
   }
-  menupopup > menu > menupopup {
-    /* TODO: Somehow unify with Linux and macOS above? */
-    margin-top: var(--nested-margin);
-    margin-inline-start: var(--nested-margin);
-  }
 }
 
 /* rules for popups associated with menulists */
diff --git a/toolkit/themes/windows/global/menu.css b/toolkit/themes/windows/global/menu.css
index bb2e79165fd2..a1c42aeb0bc2 100644
--- a/toolkit/themes/windows/global/menu.css
+++ b/toolkit/themes/windows/global/menu.css
@@ -20,8 +20,9 @@ menubar {
 menu,
 menuitem,
 menucaption {
-  flex-shrink: 0;
+  border-radius: calc(var(--panel-border-radius) / 2);
   align-items: center;
+  flex-shrink: 0;
   list-style-image: none;
 }