Version:           1.2.1 (using KDE 4.7.4) 
OS:                Linux

I am running all my updates via an apt-proxy-ng. When the proxy machine is offline and muoan tries to fetch the updates there occurs a timeout which is displayed in an error message. After that muon is locked and doesn't react any more.

Reproducible: Didn't try

Steps to Reproduce:
I am sure it happens every time. But now my system is up to date. Just configure a non existing proxy in /etc/apt/conf.d/02proxy. I have the following line in that file: 

Acquire::http { Proxy "http://192.168.1.5:3142"; };

When muon offers an update in system tray and you start the update process in muon it sill report an error after some seconds. 

Actual Results:  
All menus in muon stay grayed out.

Expected Results:  
Muon should ask for the next steps, e.g. exit or retry.

OS: Linux (x86_64) release 3.0.0-16-generic
Compiler: gcc