Bubbling drags up

[Shaun McCance <shaunm gnome org>]

Hi folks,

I'm trying to understand how drag and drop works with
when both containers and some of their children accept
drags.  It seems that if a widget accepts any drags of
any type, it blocks drags to parent widgets, even if
it doesn't accept that type of data.

I've attached a sample program that illustrates this.
It has a container that accepts drags of text/uri-list
type, and in that container is a GtkColorButton, which
has a built-in handler for application/x-color.

If you drag a file anywhere not over the color button,
you can drop it.  But you can't drop if you're over
the color button.  What I would like is for the color
button to completely ignore that drag and let it be
handled by the parent container.

Is this at all possible?

--
Shaun


#include <gtk/gtk.h>

enum {
  DRAG_TYPE_URI_LIST
};

static const GtkTargetEntry drag_types[] = {
  { "text/uri-list", 0, DRAG_TYPE_URI_LIST },
};

static void
drag_data_received (GtkWidget        *widget,
		    GdkDragContext   *context,
		    int               x,
		    int               y,
		    GtkSelectionData *selection,
		    guint             info,
		    guint             time,
		    gpointer          data)
{
  printf ("%s\n", gtk_selection_data_get_data (selection));
}

int main (int argc, char **argv)
{
  GtkWidget *window, *vbox, *label, *button;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_default_size (GTK_WINDOW (window), 400, 200);
  g_signal_connect (window, "destroy",
		    G_CALLBACK (gtk_main_quit), NULL);

  vbox = gtk_vbox_new (FALSE, 12);
  g_object_set (vbox, "border-width", 6, NULL);
  gtk_container_add (GTK_CONTAINER (window), vbox);

  gtk_drag_dest_set (vbox,
		     GTK_DEST_DEFAULT_ALL,
		     drag_types, G_N_ELEMENTS (drag_types),
		     GDK_ACTION_COPY);
  g_signal_connect_after (vbox,
		    "drag-data-received",
		    G_CALLBACK (drag_data_received),
		    NULL);

  label = gtk_label_new ("Drag a file anywhere on this window.");
  gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);

  button = gtk_color_button_new ();
  gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);

  gtk_widget_show_all (window);
  gtk_main ();
}