I was just rendering a simple cube in 2.35a, testing the different rendering options, and sometimes during rendering my mouse cursor changes to a little black box with a white 1 or l (not sure can't tell) in the bottom right cornor of the box, and blender doesn't let me do anything except move the cursor around. I have to reboot to get out of this. It's been doing it more after I installed yafray renderer and i dont even pick yafray for the renderer, I picked the default blender built-in one. ?????????????????? I'm new to this program and don't know what's going on, please help!