Date: Mon, 13 Oct 2003 14:30:20 +0100
To: lablgtk at kaba.or.jp
Subject: Bug when changing the contents of a frame
Message-ID: <20031013133019.GA26162 at redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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From: Richard Jones <rich at annexia.org>

The minimal possible case I've been able to find is below. I'm trying
to have a frame which will contain different widgets depending on
context (simulated by pressing buttons in the example
below). Everything works fine if the frame contains only simple
widgets, eg. a single button or label. However if I try to add complex
widgets (eg. vbox containing more than one widget), then the program
crashes when removing the complex widget. The error is:

Fatal error: exception Glib.Critical("Gtk", "file gtkcontainer.c: line 984 (gtk_container_remove): assertion `widget->parent == GTK_WIDGET (container)' failed")

How can I do this?

Rich.

----------------------------------------------------------------------
(* $Id: frameparent.ml,v 1.3 2003/10/13 13:26:14 rich Exp $ *)
(* ocamlc -g -w s -I +lablgtk2 lablgtk.cma gtkInit.cmo frameparent.ml -o frameparent *)

let () =
  let dialog = GWindow.dialog () in
  let vbox = dialog#vbox in
  let action_area = dialog#action_area in
  let frame = GBin.frame ~width:200 ~height:200 ~packing:vbox#pack () in
  let show i =
    (match i with
	 1 ->
	   GMisc.label ~text:"Label 1" ~packing:frame#add ()
       | 2 ->
	   let vbox = GPack.vbox ~packing:frame#add () in
	   GMisc.label ~text:"A label" ~packing:vbox#pack ();
	   GMisc.label ~text:"Another label" ~packing:vbox#pack ()
       | _ ->
	   GMisc.label ~text:"Label 3" ~packing:frame#add ()
	   :> GObj.widget) in
  let w = ref (show 1) in
  let remove () = frame#remove !w in
  let b1 = GButton.button ~label:"Show Label 1" ~packing:action_area#pack () in
  let b2 = GButton.button ~label:"Show Label 2" ~packing:action_area#pack () in
  let b3 = GButton.button ~label:"Show Label 3" ~packing:action_area#pack () in
  b1#connect#clicked ~callback:(fun () -> remove (); w := show 1);
  b2#connect#clicked ~callback:(fun () -> remove (); w := show 2);
  b3#connect#clicked ~callback:(fun () -> remove (); w := show 3);
  dialog#show ();
  GMain.main ()
----------------------------------------------------------------------

-- 
Richard Jones. http://www.annexia.org/ http://freshmeat.net/users/rwmj
Merjis Ltd. http://www.merjis.com/ - all your business data are belong to you.
'There is a joke about American engineers and French engineers. The
American team brings a prototype to the French team. The French team's
response is: "Well, it works fine in practice; but how will it hold up
in theory?"'