Comment 21 for bug 196058

Here is what I have found. First of all, I have Ubuntu 10.04 with GLX-Dock (Cairo Dock with Open-GL) installed on my system. My issue was caused when I installed the Cairo Dock add-on in Thunderbird 16.0.1, then I right clicked on my Thunderbird icon in my GLX-Dock and selected 'other actions - fullscreen'

After that, I did not get the option in the GLX-Dock, or in Thunderbird, to change it back to normal screen. What I found was that this changed the screen size settings in localstore.rdf to the following settings:

<RDF:Description RDF:about="chrome://messenger/content/messenger.xul#messengerWindow"
                   width="700"
                   height="403"
                   screenX="0"
                   screenY="3"
                   sizemode="maximized" />

I then changed filename of localstore.rdf to localstore.rdf.old and restarted Thunderbird. Thunderbird created a new localstore.rdf file on startup with the following default settings, which were correct settings to eliminate the issue.

<RDF:Description RDF:about="chrome://messenger/content/messenger.xul#messengerWindow"
                   width="1024"
                   height="711"
                   screenX="0"
                   screenY="3"
                   sizemode="normal" />

note: screenY="3" on my system because I have a hidden panel on top that is set to 3 pixels wide until I scroll over it. ScreenY would probably be "0" on most systems.