Icon of Components button wrongly drops back to closed state

In edit mode in the CM you have the Components button that opens the catalog of draggable components. In closed state the icon of that button is a sort of square with hairs on it (don't get what it should represent). After opening the catalog the icon changes to a ^-shaped form. This suggests that 'somehting that is open can also be closed', at least that is my impression.

Now drag a component from the catalog into a container. The icon next to the button changes back to the hairy block version. It should keep in the open state icon (^) until you click the button again to close the catalog.