[tde-users] Thunderbird opening minimized with Trinity desktops

I've noticed with the Debian and Ubuntu Trinity VirtualBoxes, as well as with Trinity/PCLinuxOS as the host OS, when I launch Thunderbird, it (kind of) opens minimized, taking up the left half of the screen each time and I have to select the maximize icon in the window title bar to maximize/full screen it.

With the separate install of Debian (LXQt, without Trinity), Thunderbird opens full-screen each time.

Is there a setting in Trinity that could be causing the above to occur?