Account disconnection button

[Soala]

A button on login to disconnect your account (and only your account of course) would be nice. I sometimes get disconnected on a server and then try to log back, and it simply tells me the account is already in use.
Logging on another server then coming back sometimes fixes the problem, but it's not 100% working.

I know the account remains on the server I was last for a minute or two most of the time, but today I've experienced this twice: some 4 minutes the first time, then up to 15 minutes the second time.
Which is why a button on Login to simply log you off on all servers you are on would be nice.