redisplay questions...

Ok, so I've got scrollbars (almost) working, and am going to try and tackle the redisplay weirdness I've been seeing. Basically that consists of: 1) Expose events - I _get_ all the expose events I am supposed to, but the text only appears if I obscure the Gtk XEmacs frame with a normal XEmacs frame. If I obscure then expose it using an xterm, everything (bht the modeline) shows up as just the blank background color. 2) C-l causes something similar to happen - it redraws the LINE I am on, but everything else (but the modeline) disappears. Does this ring any bells with the redisplay experts (ben, andy, jonathan)? Thanks all! -Bill P.