Seemingly randomly, an empty modal window opens while using Kontakt 7 in Logic Pro. I can't really reproduce the bug, but it probably happens after clicking on something inside Kontakt. Being modal, the window completely blocks everything else so no other window can be selected. The worst thing is that the window cannot be closed and it also prevents Logic from quitting. The only "solution" is to force quit and reopen Logic. You can see the window in the attached screen shot.