It has been a while since I upgraded VA and I did so at the same time I switched to VS 2010. I think it is VA doing this because it doesn't happen if I disable VA.
Whenever I click (don't have to double click) on a symbol it is highlighted and every other occurence of that symbol is highlighted. I can hit Esc and it turns it off, but if I don't move the cursor and scroll with the wheel the highlighting comes back on again.
Thanks, I thought I had unchecked everything that had highlighting in it already. I missed that one. That fixed what was bothering me. It is a neat feature and I wish it was easier to turn on and off, like from a right mouse menu.