QT Creator gdb debugger slow when stepping (F10 - F11)

I have a mixed "pure C++" / "QT" code application.

When debugging with step by step (F10 or F11), the debugger of "QT Creator 2.1 beta 2" is so slow that it is unusable.
Pleas consider that using "QT creator 1.3.1" the debugger goes well and fast as it's ment to be.

I attach an example.
Please consider that this example is an easy and short program (done for reporting something easy to you).
This is NOT a working program, it's only a piece of code for reporting this behaviour.
With this code, the slowing down is not so big.
With larger and more complex programs, sometimes I have to wait 20-30 seconds for a single step (F10) to be completed.
However, also with this example, I can experience dwell time of 1-3seconds while stepping through the code.

How to reproduce:

1) put a breakpoint on line 19 of the main.cpp file: p1=g.p_xy(20,30);
This is a call to the function p_xy of class g.

2) Step into this function (F11)

3) debugging with F10 this function "sometimes" (not always but almost always) takes 1-3 seconds per line.

I have seen that REMOVING line 12 ("QApplication app(argc, argv);") in main.cpp file, solve the problem for this little portion of code, and the debugger goes fluent.
Consider however, that removing this line in my "real" project doesn't solve the problem.

Last thing: please consider that the slowness that you will see in this example is almost nothing compared to the slowness I experience in my "real" project

In case you need any more test or description, please ask me.