[gnome-control-center] display: make the Apply button unsensitive for invalid configuration

[Debarshi Ray <debarshir src gnome org>]

commit 64b3fdc2fcdde46e99f657a3da1ffc7c2f7c508c
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Tue Mar 25 18:03:43 2014 +0100

    display: make the Apply button unsensitive for invalid configuration
    
    If the configuration is not applicable, due to HW constraints we
    know about, make the button insensitive, to avoid an error dialog
    later on.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=727023

 panels/display/cc-display-panel.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/panels/display/cc-display-panel.c b/panels/display/cc-display-panel.c
index 4ca89fb..d806fcb 100644
--- a/panels/display/cc-display-panel.c
+++ b/panels/display/cc-display-panel.c
@@ -1114,6 +1114,13 @@ update_apply_button (CcDisplayPanel *panel)
   gboolean config_equal;
   GnomeRRConfig *current_configuration;
 
+  if (!gnome_rr_config_applicable (priv->current_configuration,
+                                   priv->screen, NULL))
+    {
+      gtk_widget_set_sensitive (priv->apply_button, FALSE);
+      return;
+    }
+
   current_configuration = gnome_rr_config_new_current (priv->screen, NULL);
 
   /* this checks if the same modes will be set on the outputs */