I use OpenOffice 3.0.1 Writer on Windows XP on an x86 Lenovo.  Sometimes I use 
two screens, sometimes one. When I bring up the Format->Paragraph window, 
suppose I drag it to screen 2.  Suppose, later, I'm only using one screen.  
Unfortunately when I bring up the Format-Paragraph window, it tries to come up 
in its most recent location, and disappears onto the "missing" second screen, 
and there's no way to move it back, or to access it.  In fact, the only way to 
return focus back to the main Writer window is to hit "ESC", which silently 
closes the invisible window.  And the only way to access the paragraph 
formatting window is to temporarily attach a second screen so the window becomes 
visible, and drag the window back to screen 1 for future use.

Suggested behavior: when popping up any window, check if the destination screen 
(from the last use) actually exists; if not, please bring it up on screen 1.