-#toolbar-menubar:not([autohide="true"]) {
- -moz-binding: url("chrome://global/skin/globalBindings.xml#toolbar-drag-browsercustom");
+@supports ( not(-moz-appearance: -moz-mac-unified-toolbar) ) {
+ /* this is a usable workaround to detect we're on Mac OS */
+ #toolbar-menubar:not([autohide="true"]) {
+ -moz-binding: url("chrome://global/skin/globalBindings.xml#toolbar-drag-browsercustom");
+ }