You might have to either run qmake manually or edit the XML in the .ui file to remove the connection (which will be listed at the bottom of the file). Make a backup copy of the ui file first because if you mess up the editing, you will probably also break the UI itself.

This is one reason why I (and many other Qt developers, I think) don't like using automatically generated connections based on name. I don't like things that happen in code I don't see without a lot of poking around.