Can't click icons below pop up shadow area

If in Window Manager Tweaks the setting "Enable screen compositor" (not sure it is called precisely that) is enable there seem to be a shadow around pop ups etc.

If i click an icon like the volume control icon on the panel a pop op will open right next to the panel. The shadow is 16 pixels wide so i can't click the area the shadow is covering.

For example if the volume pop up is open and i click the icon next to it on the panel nothing will happen if i click within the area of the shadow. The shadow of the pop up is covering 16 pixels of the icons.