I don't know if this has already been brought up, but could we please have it so that the build menu disappears when no unit is selected? it may just be a bug, but when I deselect a constructor, the options stay. and they really take up a lot of space on my smallish monitor.
It's either a bug in the game or a bug in a mod - start by turning off any mods you have. If it is a mod, please report it on the mod's forum thread.