If "wait for transition" was checked and no valid scene was selected the
waitForTransitionChange() function will wait for its maximum allowed
duration as switcher->currentScene will never be null.
Using int is an id was getting messy with more and more conditions and
actions beeing added.
It also made the order of conditions and actions in the respective
comboboxes unchangable as there was a 1 to 1 relation of index and id.