I have nearly finished a new way to handle these icons, which will avoid these problems. It happens because each time you load the program, the part meshes are being rendered off-screen, and that doesn't work on some GPUs.
One thing you could try is seeing if you have a dual-GPU system, and if so forcing it to use the discrete (ie fast) GPU. That has helped in other threads: http://meshmixer.com/forum/index.php?topic=1570.msg3056#msg3056
Otherwise, you will have to wait...but a fix is coming!