QT 4.6.2 QGraphicsView paintEvent() not able to be triggered by update()/repaint() ?

[amoswood]

How to upgrade from qt 4.6.2 to 4.6.3 without disturbing other packages which rely on qt-dev libraries?

4.6.2 and 4.6.3 are binary compatible DLLs or SOs. So, you can simply replace the SOs in the Qt installation with some that you download from Qt. You don't have to re-compile or anything. All of this is assuming that you are not linking statically with Qt.