[gtk+] Properly update the style cascade on screen change

[Matthias Clasen <matthiasc src gnome org>]

commit 4590501854fa41a6aba4307de8808fa956305b19
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Oct 24 16:23:07 2014 -0400

    Properly update the style cascade on screen change
    
    GtkStyleContext was not properly handling the style cascade when
    setting a screen, causing the inspector global CSS to affect the
    inspector window, even though the inspector is using a different
    screen now.

 gtk/gtkstylecontext.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index 04542d7..37f330d 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -2142,6 +2142,7 @@ gtk_style_context_set_screen (GtkStyleContext *context,
 {
   GtkStyleContextPrivate *priv;
   GtkStyleCascade *screen_cascade;
+  GtkStyleCascade *old_screen_cascade;
 
   g_return_if_fail (GTK_IS_STYLE_CONTEXT (context));
   g_return_if_fail (GDK_IS_SCREEN (screen));
@@ -2151,7 +2152,8 @@ gtk_style_context_set_screen (GtkStyleContext *context,
     return;
 
   screen_cascade = _gtk_settings_get_style_cascade (gtk_settings_get_for_screen (screen));
-  if (priv->cascade == screen_cascade)
+  old_screen_cascade = _gtk_settings_get_style_cascade (gtk_settings_get_for_screen (priv->screen));
+  if (priv->cascade == old_screen_cascade)
     {
       gtk_style_context_set_cascade (context, screen_cascade);
     }