values of the actual window.
(idlwave-shell-clear-bp): Optionally skip BP query. (idlwave-shell-update-bp-overlays): Use set-window-margins instead of set-window-buffer, which incorrectly moves displayed region.
This is unrelated to redisplay; X (or GTK) dialog boxes are not managed by the redisplay engine, so there is no expectation that redisplay must occur before or after the dialog box appears. See 2007-04-23 messages on emacs-devel.