[Qt-interest] invalid drawable with Cocoa/QGLWidget

[Alan Norton]

With Cocoa on Mac OSX10.5, I get a message "invalid drawable" (and a 
defective image) whenever my QGLWidget redraws.  I have seen some 
discussion of this problem on Mac/OpenGL mailing lists, and have seen a 
recommendation to draw the window to the screen before setting the 
OpenGL context. 
However I don't know how to do this with a QGLWidget, because I can't 
control when the context is set.in the window.
Has anyone else seen this problem? 
Any ideas?
-Alan Norton