EUDORA:  closing the "Task Status" or "Mail Box" windows from the keyboard.
Press the following keys:
< Alt + T >     to open the "tools" pulldown menu,
 < K >          to place you in the "Task Status" child window,
< Shift + F10 >  to open the display menu,
< H >           to "hide" the window.
Alt + T >     to open the "tools" pulldown menu,
 <M >           to place you in the "Mail Boxes" child window,
< Shift + F10 >  to open the display menu,
< H >           to "hide" the window.
If you have the background task, this option called bring task status window
to front and bring error window to front, it will affect the focus after the
mail checking is done.