2007-06-18  Vincent Untz  <vuntz@gnome.org>

	Fix a crash when dragging a window to somewhere like another
	workspace/viewport. The original drag source widget might have been
	destroyed. We're now more solid against this, and use another drag
	source widget which lives longer.
	Fix bug #420713.

	* libwnck/pager.c: (wnck_update_drag_icon): return if the drag source
	widget is NULL
	(wnck_drag_source_destroyed): new, set the drag source widget to NULL,
	instead of keeping an invalid pointer
	(_wnck_window_set_as_drag_icon): connect to the finalization for
	drag_source. This way, we're more solid.
	* libwnck/selector.c: (wnck_selector_drag_begin): use a more long-lived
	widget for setting up the drag icon, ie the WnckSelector
	* libwnck/tasklist.c: (wnck_task_drag_begin): use a more long-lived
	widget for setting up the drag icon, ie the WnckTasklist

svn path=/trunk/; revision=1325