[gtk+] range: Fix trough state update

[Timm Bäder <baedert src gnome org>]

commit ccfc568a035a910d0ebbce7de0ea40c48a026314
Author: Timm Bäder <mail baedert org>
Date:   Mon Aug 28 11:17:19 2017 +0200

    range: Fix trough state update

 gtk/gtkrange.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index d10f3bd..8bdc93a 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -1683,6 +1683,8 @@ update_trough_state (GtkRange *range)
 
   if (priv->grab_location == priv->trough_widget)
     state |= GTK_STATE_FLAG_ACTIVE;
+
+  gtk_widget_set_state_flags (priv->trough_widget, state, TRUE);
 }
 
 static void