glFlush may make the program wait until the GL driver has forwarded all commands to the GPU. glFlush is already called once in the main loop just before swapping buffers and checking for user input.
tab_panel.py has been revised to draw glRects and draw text rendered on 2D surfaces to support 3D objects inside of filter panels.
These changes were made to support revisions in filter.py.
For more information: http://www.youtube.com/watch?v=NXN8R1BIIuk
