Have you been annoyed by the fact that KMessageBox windows always disable input to all other windows in your application, even those in another main window hierarchy? Contrary to its API documentation, KMessageBox is in fact always set as application modal. You now have another option in KDE 4.7.1 onwards.
To avoid breakage of existing applications, the decision was made to keep the existing behaviour and to modify the API docs instead to reflect the actual behaviour. But you can now specify in the Options parameter, using a new
Option enum value, that the window should be window-modal instead of application-modal. This will allow windows in a different main window hierarchy from the KMessageBox parent to remain usable.