+ /* Tell Xt not to drop PropertyNotify events that arrive for the
+ 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.
+
+ 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);
+ }
+