diff --git a/toolkit/themes/linux/global/menu.css b/toolkit/themes/linux/global/menu.css
index 0a34adfe020c..331ce178d02f 100644
--- a/toolkit/themes/linux/global/menu.css
+++ b/toolkit/themes/linux/global/menu.css
@@ -80,7 +80,7 @@ menucaption {
 /* ::::: menu/menuitems in menulist popups ::::: */
 
 menulist > menupopup {
-  font: inherit;
+  font: message-box;
 }
 
 menulist > menupopup > menuitem,
diff --git a/toolkit/themes/windows/global/menu.css b/toolkit/themes/windows/global/menu.css
index 84df058c219f..8825ddcadb39 100644
--- a/toolkit/themes/windows/global/menu.css
+++ b/toolkit/themes/windows/global/menu.css
@@ -170,7 +170,7 @@ menuitem[_moz-menuactive="true"] {
 /* ::::: menu/menuitems in menulist popups ::::: */
 
 menulist > menupopup {
-  font: inherit;
+  font: message-box;
 }
 
 menulist > menupopup > menuitem,