collidingMice in the set of graphicsView examples crashes on Mac OS X

1. Find example program
/examples/graphicsview/collidingmice

2. change main.cpp
@@-48,1 +48,1@@

• static const int MouseCount = 7;
  + static const int MouseCount = 70;

3.Build with Qt 4.6.2 or Qt 4.6.1 and run

4. Press on the title bar, keeping the mouse pressed move the window

5.Release the mouse

====> the window moves while the mouse button is released
====> move the mouse long enough and the program will crash with the following crash report

sorry if this bug has already been logged