Button assignment steals mouse clicks

[brecht]

The button assignment menu pops up when:

• the Mouse preferences window is open, and

• a window is in front of it, and

• the pointer is in the area where the mouse buttons were in the image on the Mouse preferences window

• a mouse button is pressed

The same happens if the Mouse preferences window is minimized. Clicking on the desktop or a window in the right area will pop up the menu.

[stippi]

Fixed in hrev29430.

[luroh]

Confirmed fixed.