[gtk+] scrolledwindow: Deny scrolling sequences if pressed on the scrollbars

[Carlos Garnacho <carlosg src gnome org>]

commit 3b636cbeb99f23214aec8e26c194d2998ebb9da2
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Jun 12 15:17:47 2014 +0200

    scrolledwindow: Deny scrolling sequences if pressed on the scrollbars
    
    Scrollbars might be a bit too narrow for touch (and generally less useful
    besides kinetic scrolling), but those should be functional nevertheless.

 gtk/gtkscrolledwindow.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index 66c9de6..87d3008 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -578,20 +578,26 @@ scrolled_window_drag_begin_cb (GtkScrolledWindow *scrolled_window,
   GtkScrolledWindowPrivate *priv = scrolled_window->priv;
   GtkEventSequenceState state;
   GdkEventSequence *sequence;
+  GtkWidget *event_widget;
+  const GdkEvent *event;
 
   priv->in_drag = FALSE;
   priv->drag_start_x = priv->unclamped_hadj_value;
   priv->drag_start_y = priv->unclamped_vadj_value;
   gtk_scrolled_window_cancel_deceleration (scrolled_window);
+  sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
+  event = gtk_gesture_get_last_event (gesture, sequence);
+  event_widget = gtk_get_event_widget ((GdkEvent *) event);
 
-  if (!priv->hscrollbar_visible && !priv->vscrollbar_visible)
+  if (event_widget == priv->vscrollbar ||
+      event_widget == priv->hscrollbar ||
+      (!priv->hscrollbar_visible && !priv->vscrollbar_visible))
     state = GTK_EVENT_SEQUENCE_DENIED;
   else if (priv->capture_button_press)
     state = GTK_EVENT_SEQUENCE_CLAIMED;
   else
     return;
 
-  sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
   gtk_gesture_set_sequence_state (gesture, sequence, state);
 }