Error in MOC file

[Computer Hater]

Hi,
I have the following problem using Qt Creator:

In my menu I added an option for testing actions associated with it. I removed the option again (I think I first removed the action from the Action Editor, then the menu option itself).
Ever since then I've been getting a compiler error that is actually referring to the file "moc_mainwindow.cpp", so it's in an auto-generated file (see "moc file error.jpg").
I also removed some other actions from the Action Editor, but I only get an error for this one.

AFAIK I have removed every remnant of that option from all visible elements in the design area (see "mainmenu design.jpg"), so I would expect them to be removed behind the scenes, i.e. in auto-generated files, as well. Yet the compiler seems to still find it somewhere and include it when generating dependent files. Apparently I have to remove it manually before the program will compile. But where ?

Thanks in advance.