Finding this bug a lot recently. Basically I will be working in a file and the tool panels won't display, you can right click and see the the pop ups but nothing appears. Likewise if you have two or more documents open and switch between them, the screen stays the same. It says I'm on the new document but it doesn't change. The only way to fix it is to close and restart the program. I also get it with photoshop. Both at work and home. I'm essentially running the same software/hardware at either site. 27" iMac 16GB, 32gb RAM, 4GB graphics card. Latest OS.