Start by dragging an open tab downwards, and releasing. This creates a second ST2 window.
Now try to use the Goto Anything Pane. The only thing it can find is files open in that second window.
Additionally, my builder doesn't work when triggered from the secondary window. It gives the Errno 2, No such file or directory. Building from the same file in the primary window works as expected.
While we're on the subject, it would be nice if emptied out "extra" windows would just go away - I always wind up with a few orphans