bug 1: just start qt creator and enter full screen mode you will not be able to open any menu now you can only exit full screen mode my its shortcut

bug 2: start a task manager program (e.g. in my case process explorer form sysinternals.com) press and hold the find process button and drag on qt creators window it goes totally white and unusable until next paint event (e.g. until you move your mouse on a button)

that was all for now note that i compiled older qt creator versions with Qt 5.5.1 but the does have better window system and none of this bugs