When in a large assembly (500 parts or so), and I left mouse click on a part or subassembly in the feature tree, the "context menu" pops up. I have it set to "Show on selection". When I click one of the icons in this popup menu as I would at a normal speed nothing happens. There seems to be a lag from when the menu is displayed and when it is actually active. If I hover over one of the icons for about 2 seconds and then click on it, then it will recognize the mouse click. The popup menu works fine in a small assembly.
If we use the full menu for our selections instead of the popup menu, the mouse clicks function fine.
Several of us are experiencing this. We are using SW 2010 SP4.0.