Apologies if this is already well documented -- I didn't see it.
You didn;t see it because it is not a problem with Xcode but with your setup Do you honestly think a sequence like you described, if it was a bug, would not be plastered all over the place?
If you want to try and fix it you can start by describing your system and OS versions, what other development tools are installed and when the problem started/
Then log in as different user in a clean new account, the guest user works well for this and try the same key strokes there. Report back the results.