QQuickWidget sample doesn't run correctly on MacOS X multi display environment

When there are two displays, Mac OS X opens application windows on the display that has mouse cursor.

The following steps make QQuickWidget white. No rectangle appears.

1. Move Qt Creator to an external display
2. Press "Run Debug" button
3. Only QQuickWidget becomes white. QLCDNumber works fine.
4. Move the window to the internal display, it is still white.

The following steps, QQuickWidget works

1. Move Qt Creator to an internal display
2. Press "Run Debug" button
3. Sample window appears in internal display and works correctly.
4. Move the window to the external display, it still works fine.