Hi, please try the following: 1) Start XEmacs with -vanilla 2) Devide *scratch*-buffer into two windows 3) insert (setq debug-on-error t) and hit C-x C-e 4) Do C-s <a word in the scratch-buffer>. Do not finish the isearch, i.e. do not RET or C-g so ensure the found word appears highlighted 5) Click with middle mouse-button in the other window ==> You get an error 6) Go with C-x b to the *Backtrace*-buffer 8) Now hit q 9) Now do M-x and then hit TAB for example. then you should get: Signaling: (args-out-of-range #<buffer " *Minibuf-0*"> 8 178) set-extent-endpoints(#<extent [detached) 0x1d551c4 from buffer *scratch*> 8 178 #<buffer " *Minibuf-0*">) isearch-highlight(8 178) isearch-update() isearch-search-and-update() isearch-process-search-string(" " "^I") isearch-process-search-char(#<keypress-event tab>) #<compiled-function nil "...(21)" [this-command last-command-event event isearch-whitespace-chars event-to-character character-to-event ?\ isearch-process-search-char] 2 365487 nil>() call-interactively(isearch-printing-char) read-minibuffer-internal("Find file: ") byte-code("..." [standard-output standard-input prompt recursion-depth minibuffer-depth t read-minibuffer-internal] 2) read-from-minibuffer("Find file: " "c:\\tmp\\" #<keymap read-file-name-map size 2 0xcec> nil file-name-history nil nil) read-file-name-2(file-name-history "Find file: " nil nil nil nil read-file-name-internal) read-file-name-1(file file-name-history "Find file: " nil nil nil nil read-file-name-internal) read-file-name("Find file: " nil nil nil) call-interactively(find-file) For me this looks like an not wanted behavior - it seems that changing window rsp. buffer (either with mouse or not - i have not tested this exactly) when a not finished isearch is "open" cause some errors.... IMHO XEmacs should be able to handle this error free... Ciao, Klaus Klaus Berndl mailto: klaus.berndl(a)sdm.de sd&m AG http://www.sdm.de software design & management Carl-Wery-Str. 42, 81739 Muenchen, Germany Tel +49 89 63812-392, Fax -220