There seems to be other problems in XEmacs' gud.el 1) comint-output-filter-functions do not work correctly. "Eric" == Eric Ludlam <eludlam(a)mathworks.com&gt; writes: Eric> This is a bug in XEmacs' gud.el file. I checked the Eric> Emacs gud.el, and it's gud-filter explicitly calls Eric> comint-output-filter, which in turn calls the hooks. Eric> In XEmacs gud.el, gud-filter explicitly calls Eric> insert-before-markers, thus skipping the whole comint part. 2) - In one frame two windows, in other window there is matlab-shell buffer and in other window some m-file - In matlab-shell "dbstop if error" - Focus in m-file and use matlab-shell-run-region to run some code which calls some function having error - matlab-shell/gud combo fails to arrange windows correctly in this case. The file having error is opened in window where matlab-shell was and. I think that better way would be to change the focus in to the matlab-shell buffer and open the file having error to window where the m-file was. "Eric" == Eric Ludlam <eludlam(a)mathworks.com&gt; writes: Eric> I also noticed similar behavior under XEmacs. I set a Eric> frame variable, and wrote a find-file function (which Eric> find-file-noselects the file) and then GUD pops the buffer Eric> forwards afterwards. My quick foray into gud-filter was Eric> unrevealing. I'm curious to know if other debuggers under Eric> XEmacs do the same thing. I'll have to poke around. These are fixed in Emacs' gud.el but as said it does not yet work in XEmacs... Ave