No reaction on RMB click when Start menu is open

If you have Start menu open and try to close it clicking the right mouse button on outside area, Start won't go away and RMB event is not passed afterwards.

How to reproduce:

1. Open Start menu.
2. Click anywhere outside the Start menu with right mouse button

Expected behavior:
Start menu is closed, RMB event is going to window where you have clicked the right mouse button

Actual behavior:
RMB is ignored, Start menu stays open.