Locator menu shown on windows which don't have a Locator edit

1. Open the "About Qt Creator" dialog.
2. Press Ctrl+K to use the Locator.
   Instead of in its usual place, the Locator will appear right on top of the "About Qt Creator" dialog.

The position of the Locator should be tied only to windows which show a Locator edit. If the current which does not have such, Creator's main window should be used. (It would be better to use the most recent window with a Locator edit, but that might not be possible with reasonable effort.)