1. Install Qt 5.1 RC for MSVC2010 including sources.
2. Open a project which includes the following lines (taken from qbytearray::testQByteArray1() in tests\manual\debugger\simple\simple_test_app.cpp) and configure it with a kit using the Qt version from step 1:

   QByteArray ba;
   ba += "Hello";
   

3. Set a breakpoint in the second line and let the debugger run up to there.
4. Try to step into QByteArray::operator+=.
   Creator will step out.

Creator should step into the function. If this is not possible for some reason, it should just step over, not out.