If I knew what it was called I would search for it. Coworker just asked how to turn on the feature for a part to show in the tree when he selects it on the monitor.
I thought it would be dynamic highlighting but he said that option is greyed out. What should I be looking for?
If Dynamic Highlight is grayed out, then I would say that he has large assembly mode going, or he has Use Software OpenGL checked.
Can you verify if he has "Use Software OpenGL" Checked?