I've played with XEmacs-21.0.67 a little bit and I found that if
immediately after I start it I try to maximize the window, the
maximize event will be lost - although the frame will be maximized,
XEmacs will keep using only its left part, with the scrollbar drawn
somewhere in the middle.
I could only reproduce this only if my .emacs is in place. Without it
XEmacs loads too fast for me to be able to double-click on its window
title to maximize it.