Fix the menu and sub-menu pop-up sizing behavior.
Fix the menu and sub-menu pop-up sizing behavior.

Apart from properly taking into account for the width of the border don't force
the width to something that would not fit the contents anyway. Simplify and
document the algorithm and reasoning.


Linaro/lava-server,OSSystems/lava-server,OSSystems/lava-server,Linaro/lava-server,OSSystems/lava-server,Linaro/lava-server,Linaro/lava-server