[gnome-panel] [panel] Check if the current monitor of a toplevel can be still used

[Vincent Untz <vuntz src gnome org>]

commit e5d41e1cf56445c451f78b83ec0f4bf92fdef604
Author: Vincent Untz <vuntz gnome org>
Date:   Wed Aug 19 15:45:10 2009 +0200

    [panel] Check if the current monitor of a toplevel can be still used
    
    On a randr update, we were checking if we can move a toplevel to its
    configured monitor. But we were not checking if its current monitor was
    still valid (the opposite case, when a monitor disappears).

 gnome-panel/panel-toplevel.c |   29 +++++++++++++++++------------
 1 files changed, 17 insertions(+), 12 deletions(-)
---
diff --git a/gnome-panel/panel-toplevel.c b/gnome-panel/panel-toplevel.c
index cb75e4d..64d24bf 100644
--- a/gnome-panel/panel-toplevel.c
+++ b/gnome-panel/panel-toplevel.c
@@ -5025,9 +5025,9 @@ panel_toplevel_set_monitor_internal (PanelToplevel *toplevel,
 /**
  * panel_toplevel_update_monitor:
  *
- * Moves the toplevel to its configured monitor if needed. This generally
- * happens when the configured monitor was non-existing before, and it appeared
- * at runtime.
+ * Moves the toplevel to its configured monitor or the first one, if needed.
+ * This generally happens when the configured monitor was non-existing before,
+ * and it appeared at runtime, or if it was existing and disappeared.
  *
  * This must only be called at the beginning of the size request of the
  * toplevel because it doesn't queue a size request.
@@ -5037,17 +5037,22 @@ panel_toplevel_update_monitor (PanelToplevel *toplevel)
 {
 	GdkScreen *screen;
 
-	if (toplevel->priv->configured_monitor == -1 ||
-	    toplevel->priv->configured_monitor == toplevel->priv->monitor)
-		return;
-
 	screen = gtk_window_get_screen (GTK_WINDOW (toplevel));
-	if (toplevel->priv->configured_monitor >= panel_multiscreen_monitors (screen))
-		return;
 
-	panel_toplevel_set_monitor_internal (toplevel,
-					     toplevel->priv->configured_monitor,
-					     FALSE);
+	/* If we were not using the configured monitor, can we use it now? */
+	if ((toplevel->priv->configured_monitor != -1) &&
+	    (toplevel->priv->configured_monitor != toplevel->priv->monitor) &&
+	    toplevel->priv->configured_monitor < panel_multiscreen_monitors (screen)) {
+		panel_toplevel_set_monitor_internal (toplevel,
+						     toplevel->priv->configured_monitor,
+						     FALSE);
+
+	/* else, can we still use the monitor we were using? */
+	} else if (toplevel->priv->monitor >= panel_multiscreen_monitors (screen)) {
+		panel_toplevel_set_monitor_internal (toplevel,
+						     0,
+						     FALSE);
+	}
 }
 
 void