I develop on OSX for OSX/Android/iOS. I have Qt versions 5.5.1 and 5.6 prereleases installed, so I switch kits a lot looking for regressions.

Many times when I switch kits, the three icon sin the bottom left get disabled, which is normal while it parses the project. After parsing they are supposed to be re-enabled. Many times they are not. Sometimes the build icon is enabled, and when doing so, the compile pane says "Nothing to be done...". Running qmake doesn't seem to fix it either. The only fix aside from editing is switching back and forth between kits until it end up with the buttons correct.