Code review comment for lp:~widelands-dev/widelands/notifications_buildingwindows

Next try - should be all fixed now.

> Minor nit (can be ignored): When the building is finished, the (minimized) window is brought to the front (!= maximized). Not really a problem in my opinion.

We will probably have to dig into the UI toolkit for that, so let's leave it for later and see if it annoys anybody.