too many dialogs opened for 'room has reached maximum number of users'
Bug description
If you joined some chat where maximum number of users has been reached for this, gajim opens dialog window with "Maximum number of users for room@server has been reached" message about every second.
Steps to reproduce
1, Join a room where maximum number of users has been reached
2, go to sleep
3, wake up in the morning and try to close all the dialogs
Software versions
OS version: Gentoo linux ~x86
GTK version: 2.18.9
PyGTK version: 2.16.0