[Qt-interest] custom OpenGL widget update blocks other Qt GUI rendering

[Artem Kharitonyuk]

Have the same problem.
We implement gui for our raytracer with QT and we have preview window that 
renders using OpenGL (QGLWidget). Rendering is updated by the timer. For simple 
scenes everything is OK, but for really complex ones (> 10M triangles), when one 
frame takes > 100ms to render, we have a problem - open file dialog simply 
failed to draw itself - only some parts of it are appeared and than entire app 
stops responding.