Supress / Collect Errors
When there's an error (e.g. UnicodeDecode error on roster,..) it tends to pop up 20+ Windows with the same error message.
It seems to happen with errors on roster names (non-utf8 for example) which causes multiple boxes e.g. when typing as you search contacts
I propose to suppress (and/or collect) those messages if they come up within a few seconds of each other (maybe just add something like "This error repeated X times" to the dialogue, or just quietly swallow them as I suspect noone cares normally - once is enough)