Never mind, after some hexediting (deleting the positions part in HKEY_CURRENT_USER\Software\Allround Automations\PL/SQL Developer) i was good to go again.
Right now when I click on query results in the sql window grid (on the '...' button), my plsql developer loses focus, I actually notice a modal screen being focused in the background (I can't type or click without getting a beep from windows 7 plus the borders are flashing shortly like they do...