[gnome-documents] nav-bar: fix an error in positioning the preview window

[Cosimo Cecchi <cosimoc src gnome org>]

commit 59c26bdc297c8f7852f4610b82dca5f43b1f7174
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Fri Feb 8 20:26:25 2013 -0500

    nav-bar: fix an error in positioning the preview window

 src/lib/gd-nav-bar.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)
---
diff --git a/src/lib/gd-nav-bar.c b/src/lib/gd-nav-bar.c
index ed8907a..c822e05 100644
--- a/src/lib/gd-nav-bar.c
+++ b/src/lib/gd-nav-bar.c
@@ -677,11 +677,12 @@ hide_preview (GdNavBar *self)
 static void
 show_preview (GdNavBar *self)
 {
-        GdkWindow *window;
+        GdkWindow *window, *toplevel_window;
+        GtkWidget *toplevel;
         int x, y;
         int width, height;
         int bx, by;
-        int rx, ry;
+        int tx, ty;
 
         gtk_widget_realize (self->priv->preview_window);
 
@@ -689,11 +690,14 @@ show_preview (GdNavBar *self)
         height = gtk_widget_get_allocated_height (GTK_WIDGET (self->priv->preview_window));
 
         window = gtk_widget_get_window (GTK_WIDGET (self));
-        gdk_window_get_root_origin (window, &rx, &ry);
         gdk_window_get_position (window, &bx, &by);
 
-        x = rx + bx + (gdk_window_get_width (window) - width) / 2;
-        y = ry + by - height + 10;
+        toplevel = gtk_widget_get_toplevel (GTK_WIDGET (self));
+        toplevel_window = gtk_widget_get_window (toplevel);
+        gdk_window_get_origin (toplevel_window, &tx, &ty);
+
+        x = tx + bx + (gdk_window_get_width (window) - width) / 2;
+        y = ty + by - height - 10;
 
         gtk_window_move (GTK_WINDOW (self->priv->preview_window), x, y);
         gtk_window_present (GTK_WINDOW (self->priv->preview_window));