QML element PinchArea breaks fullscreen mode on Mac platform

Create a simple helloworld application with Qt Creator Wizard (new Project / Qt Quick 2 Application (Built-in Elements) and add this :

• in main.cpp just before instruction 'viewer.showExpanded()' add 'viewer.setFlags(viewer.flags() | Qt::WindowFullscreenButtonHint);'
• in main.qml add an empty element 'PinchArea{}'

Run the app : the fullscreen mode is not available.
Remove PinchArea element in main.qml, run the app : the fullscreen mode is available (double arrow in top-right corner of the window).
Calling directly showFullscreen() gives the same result.

Note : Not reproduced with Qt 5.0.1.
Note : Not reproduced on Windows platform.