[gtk+/native-layout] GtkToolPalette: Fix a compiler warning introduced in my last commit.

[Tristan Van Berkom <tvb src gnome org>]

commit 2a762bf6ca8e429c70da2dc99b0945801c7043ff
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Jan 19 09:04:15 2010 +0100

    GtkToolPalette: Fix a compiler warning introduced in my last commit.

 gtk/gtktoolpalette.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtktoolpalette.c b/gtk/gtktoolpalette.c
index 9bb93d9..94ea452 100644
--- a/gtk/gtktoolpalette.c
+++ b/gtk/gtktoolpalette.c
@@ -1549,12 +1549,13 @@ gtk_tool_palette_get_drop_item (GtkToolPalette *palette,
                                 gint            x,
                                 gint            y)
 {
-  GtkWidget *group = gtk_tool_palette_get_drop_group (palette, x, y);
+  GtkToolItemGroup *group = gtk_tool_palette_get_drop_group (palette, x, y);
+  GtkWidget *widget = GTK_WIDGET (group);
 
   if (group)
-    return gtk_tool_item_group_get_drop_item (GTK_TOOL_ITEM_GROUP (group),
-                                              x - group->allocation.x,
-                                              y - group->allocation.y);
+    return gtk_tool_item_group_get_drop_item (group,
+                                              x - widget->allocation.x,
+                                              y - widget->allocation.y);
 
   return NULL;
 }