I know a lot of us have been wanting to press enter after typing an expression in the event wizard to close it. Turns out it works when the icon section of the screen is selected, so if you press tab first after typing, it selects that area, then you can press enter. Well, as long as there isn't another text field that it selects first.
Secondly, the issue of the 'hairline' placement in the event editor - from what I can tell, it's actually based upon if the previous movement the mouse made was up or down. So if it goes up any number of pixels, the line shows up at the top.