look at this:
http://www.qtforum.org/article/26669/qt4-mess-up-the-opengl-context.html
even on qt forum noone knows how to resolve this bug
look at this:
http:// www.qtforum. org/article/ 26669/qt4- mess-up- the-opengl- context. html
even on qt forum noone knows how to resolve this bug