Recently I did something so my standard Thunderbird e-mail message pane disappeared. I was not sure what happened so my logical guess was I had to do something from View menu, i.e. change something in:
View -> Layout or
View -> Toolbars
Anyways after taking close look in View, I realized can't fix it from there. So tried changing settings in:
Edit -> Preferences -> Advanced (tab)-> Reading & Display
I tried changing setting for Open messages in with no luck. Finally after some more googling I got the fix under Mozilla Community Q&A site here. The fix is as simple as pressing F8Pressing F8 makes e-mail message pane appear or disappear, like shown in below screenshots ….
That's all problem solved