This behavior has been annoying me ever since 10.0,
When you attempt to change a filename extension, the Finder warns you of the danger of doing so by poping up a modal dialog box. If you choose to go on with the change, you end up in the Finder with your pointer marking a selection (as the mouse button was pressed down - but it isn't!).
I know it just requires an extra click to cancel the selection area, but it bugs me. I've ended up with files moved, or displays scrolled. Bugs me.