QGraphicsItem and QGraphicsProxyWidget are not rendered in stable condition within QGraphicsScene under OpenGL viewport.

The condition often occurs when the widget or item content being updated and needs to be redrawn. Only partial or none of the content are correctly rendered. Out of border content of QGraphicsProxyWidget are not correctly clipped. For example, the web page content that is larger the size of QWebView will still being drawn; QML animation are not correctly updated.

The issue often comes with the sign of frame rate degration, from 40-50 FPS suddenly dropped to 10. However, after checking the code, there's no evidence of heavy computation. A plain QWebView (http://labs.trolltech.com/blogs/2008/07/03/putting-qtwebkit-to-use-with-google-maps/) or QML flippable example could easily trigger such problem.

Attachment comes with the comparison between N900 and Desktop environment with the same code.