Unconfirmed transactions are only grey when you receive them. They don't count toward your balance, since they might never clear.
I have an
outgoing transaction that is grey. Is that some kind of error?
By the way, this is using the official 0.3.20.2 binary that was downloaded from bitcoin.org when that version was current.
Edit: Just tried in 0.3.21 with the same result, and have tried -rescan.
Then I tried the new -purgetx and it has removed it for me.