I am working in a fairly large architectural model. When zooming in elevation or rotating in a 3D view, there is one floor slab that will somehow get selected (without the cursor being anywhere near it and without clicking in the view), which then causes the model to freeze up for several minutes. It is always the same floor, even though there are 7 levels with multiple floors. It eventually recovers, but it happens often and is frustrating and time consuming. Yes, I can disable selecting pinned objects, but that doesn't answer why it happens. Any ideas?