Windows 7, Sublime 2.0.1
1. Open two column views with text in them.
2. In view 2, first click on any symbol, for example a variable name.
3. The focus switches to view 2 and the cursor is where you clicked. Good.
4. Now double click on the same symbol to "select" it.
5. In view 1, double click on some other symbol. The focus and cursor moves as expected. Good.
6. Now, try to double click on the original symbol (still highlighted) in view 2. Notice the focus remains in view 1.
7. Keep double clicking on it if you want but the focus will stay in view 1.
8. Double click on a different symbol in view 2 and everything will be fine again.
This doesn't only happen with double clicking, but it's easiest to demonstrate.
Summary: clicking on a previously selected piece of text in an out-of-focus view prevents focus from changing to that view.
This is happening to me all the time because I've been copying symbols from one view and replacing them in another view.
PS. sublime text 2 is brilliant