I have found a way to deal with dialog boxes appearing in openoffice.org running under lxde not fitting to the screen:

In the terminal open in lxde type:

xmodmap -e "keysym ISO_Level3_Shift = Alt_L"

Now Alt-space will pop-up the window operations menu. Using the stylus, choose move, and you can move the dialog around. It works also when the title bar is outside of the screen.

It could probably be put in some startup file.
Leaving only the left, vertical panel, adding the menu to it and removing the top panel leaves much more screen area for the editor, you can also remove decorations from the editor window.