Display format "Displayed" does not work for QImage with Qt 5.1.1

1. Open simple.pro from Creator's repository.
2. Set a breakpoint on the last code line of function testQImageDisplay().
3. Let the debugger run into this breakpoint.
4. For the object named "im", set display format to "Displayed".
   A small window will open which shows a gray (?) rectangle.
   I tried with the binary package of Qt 5.1.1 which was built with MinGW gcc 4.8.

Instead, it should display the content of the QImage named "im", a black smiley on red background. With my own builds of Qt 4.8.4 using MinGW gcc 4.4, or Qt 4.8.5 using MinGW gcc 4.8 this works fine.