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?