Waiting on non-QT events.

I have written an app for checking my email, and it laggs when I am
downloading from the server and I am curious how to avoid this.

The general layout is 
EmailWidget (Qwidget with a layout)
	.ImapTool
	.MessageList(QlistView)
	.MailBoxList(QlistView)
	def RefreshMessageList()

 I double click the MailBoxList it emits a signal that Email Widget is
connected to which then calls the ImapTool to query the imap server.
This stops everything, the lists freeze and I can't do anything until
the imap routine finishes.  
Could this be avoided using more signals.  Like have the ImapTool as a
separate QObject that emits a signal when finish?.

thanks
mbs