When gpg is not working, we cannot remove gpg key from configuration.
I moved my Gajim configuration from one host to another, but without gpg keys. So now I've got Gajim that knows I was using gpg and it asks for gpg passphrase. Of course I've got no keys, so whatever I type as passphrase, Gajim says I will be connected without gpg.
But I went to account manager and tried to turn off gpg. When clicking on "Choose key" button, I get an error dialog and I get nothing, so seems that there is no way to stop Gajim from bugging me to use gpg (other than ACE). There should be at least a dialog like "It seems you don't have gpg, do you want to turn it off?". Another way is that Gajim shouldn't ask for passphrase when gpg is not configured.