Small Resolution Screens
Smaller devices (such as netbook and notepad computers) often have a screen resolution of 1024 x 600 or less. Thunderbird is not yet optimized to display at this resolution. Some windows (such as the Account Settings dialog) are only partially displayed. You may not be able to see all the fields and buttons on these windows. Typically, the lower portion of the dialog is off the screen.
To work around this problem, Thunderbird community contributor Anders Vinther discovered that if you set the computer's application display size to a smaller font, the window will re-size and be completely displayed. Anders has published articles on his site describing this workaround: