Clicking toolbar menu button does not close expanded menu?

If I click on a toolbar-menu-button, it will expand the menu.
Suppose I am done looking at the expanded menu.
I would like to click the button again to close the expanded menu.

Instead what happens is that a subsequent click causes the menu to be re-opened. I cannot close expanded menus unless I click areas like the desktop or empty toolbar space.

How can I set the toolbar-menu-button to also close menus that are open?