#107 glut full-screen mode conflicts with DM

[zhu]

I have a molecular displaying program, i.e. pymol. It uses opengl to
display the 3D molecules. When I put the program in full-screen
mode (glut full-screen mode), and then switch virtual desktop by
DM, every virtual desktop is full-screen pymol. If I play a movie by
full screen and switch virtual desktop, it is just fine.

So somehow, DM conflicts with glut full-screen mode.