QmlProfiler sometimes fails to start inferior

Steps to reproduce:

1. make sure you have 2 Qt5 kits (I'm using Qt5.0.1 and Qt5.1.0)
2. create/open Qt Quick 2 UI
3. switch to Analyze view
4. start profiling the app with kit1 (Qt5.0.1)
5. click into the app to close/stop profiling
6. start again and use 'Stop profiling' button this time
7. do the same after switching to the other kit
8. start over at 4.
9. if QmlScene always starts - try to run the application with Qt5.0.1 before profiling it again

Current result:

• sometimes QmlProfiler starts QmlScene but no window appears at all (I can see QmlScene only inside the Dock)

Expected result:

• QmlProfiler can start QmlScene (including inferior) and window appears always