I've found on Swift 4.2.5 that if I have multiple files open then Swift will periodically jump between them at random. It seems to get worse the more files I have open, though it will happen with only 2. It also seems more likely to happen if I have search results open.

Also Swift will complain that B-em has failed to launch when it has in fact succeeded. This is particularly frustrating as it will grab the focus when this happens, which is irritating if I want to quickly start the B-em debugger or something.

Also the Swift window keeps jumping into the foreground and grabbing focus, even if it's in the background.