APPROVE COMMIT NOTE: This patch has been committed. src/ChangeLog addition: 2005-03-02 Aidan Kehoe <kehoea(a)parhasard.net&gt; * select-x.c (x_reply_selection_request): Check that XtWindowToWidget returns NULL before calling XtRegisterDrawable, document why. XEmacs Trunk source patch: Diff command: cvs -q diff -u Files affected: src/select-x.c Index: src/select-x.c =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/src/select-x.c,v retrieving revision 1.22 diff -u -u -r1.22 select-x.c --- src/select-x.c 2005/03/02 13:06:40 1.22 +++ src/select-x.c 2005/03/02 18:29:25 ＠＠ -545,8 +545,24 ＠＠ target window, rather, pass them to us. This would be a hack, but the Xt selection routines are broken for our purposes--we can't pass them callbacks from Lisp, for example. Let's call it a - workaround. */ - XtRegisterDrawable(display, (Drawable)window, widget); + workaround. + + The call to wait_for_property_change means we can break out of that + function, switch to another frame on the same display (which will + be another Xt widget), select a huge amount of text, and have the + same (foreign) app ask for another incremental selection + transfer. Programming like X11 made sense, would mean that, in that + case, XtRegisterDrawable is called twice with different widgets. + + Since the results of calling XtRegisterDrawable when the drawable + is already registered with another widget are undefined, we want to + avoid that--so, only call it when XtWindowToWidget returns NULL, + which it will only do with a valid Window if it's not already + registered. */ + if (NULL == XtWindowToWidget(display, window)) + { + XtRegisterDrawable(display, (Drawable)window, widget); + } prop_id = expect_property_change (display, window, reply.property, PropertyDelete); -- “I, for instance, am gung-ho about open source because my family is being held hostage in Rob Malda’s basement. But who fact-checks me, or Enderle, when we say something in public? No-one!” -- Danny O’Brien