[glade] Bug 760610: Disable scroll events on property editor widgets

[Tristan Van Berkom <tvb src gnome org>]

commit 094997593cdc006d6f2ba0d5179f223518e56264
Author: Tristan Van Berkom <tristan upstairslabs com>
Date:   Thu Jan 28 14:30:42 2016 +0100

    Bug 760610: Disable scroll events on property editor widgets
    
    As described in the bug, this is only harmful and annoying that
    combo boxes handle scroll events, of course, the whole purpose
    of combo boxes is to place them inside scrolled windows ;-)

 gladeui/glade-editor-property.c |   38 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)
---
diff --git a/gladeui/glade-editor-property.c b/gladeui/glade-editor-property.c
index ea32130..092194a 100644
--- a/gladeui/glade-editor-property.c
+++ b/gladeui/glade-editor-property.c
@@ -920,6 +920,40 @@ glade_eprop_numeric_force_update (GtkSpinButton       *spin,
   g_free (text);
 }
 
+/* Use this to disable scroll events on property editors,
+ * we dont want them handling scroll because they are inside
+ * a scrolled window and interrupt workflow causing unexpected
+ * results when scrolled.
+ */
+static gint
+abort_scroll_events (GtkWidget *widget,
+                    GdkEvent  *event,
+                    gpointer   user_data)
+{
+  GtkWidget *parent = gtk_widget_get_parent (widget);
+
+  /* Removing the events from the mask doesnt work for
+   * stubborn combo boxes which call gtk_widget_add_events()
+   * in it's gtk_combo_box_init() - so handle the event and propagate
+   * it up the tree so the scrollwindow still handles the scroll event.
+   */
+  gtk_propagate_event (parent, event);
+
+  return TRUE;
+}
+
+static void
+remove_scroll_events (GtkWidget *widget)
+{
+  gint events = gtk_widget_get_events (widget);
+
+  events &= ~(GDK_SCROLL_MASK | GDK_SMOOTH_SCROLL_MASK);
+  gtk_widget_set_events (widget, events);
+
+  g_signal_connect (G_OBJECT (widget), "scroll-event",
+                   G_CALLBACK (abort_scroll_events), NULL);
+}
+
 static GtkWidget *
 glade_eprop_numeric_create_input (GladeEditorProperty *eprop)
 {
@@ -940,6 +974,7 @@ glade_eprop_numeric_create_input (GladeEditorProperty *eprop)
   gtk_entry_set_activates_default (GTK_ENTRY (eprop_numeric->spin), TRUE);
   gtk_spin_button_set_numeric (GTK_SPIN_BUTTON (eprop_numeric->spin), TRUE);
 
+  remove_scroll_events (eprop_numeric->spin);
   gtk_widget_show (eprop_numeric->spin);
 
   /* Limit the size of the spin if max allowed value is too big */
@@ -1093,6 +1128,7 @@ glade_eprop_enum_create_input (GladeEditorProperty *eprop)
   g_signal_connect (G_OBJECT (eprop_enum->combo_box), "changed",
                     G_CALLBACK (glade_eprop_enum_changed), eprop);
 
+  remove_scroll_events (eprop_enum->combo_box);
   gtk_widget_show_all (eprop_enum->combo_box);
 
   g_type_class_unref (eclass);
@@ -2358,6 +2394,7 @@ glade_eprop_text_create_input (GladeEditorProperty *eprop)
       gtk_widget_set_halign (hbox, GTK_ALIGN_START);
       gtk_widget_set_valign (hbox, GTK_ALIGN_CENTER);
       gtk_widget_set_hexpand (combo, TRUE);
+      remove_scroll_events (combo);
       
       eprop_text->store = (GtkTreeModel *)
           glade_eprop_text_create_store (glade_property_class_stock (klass) ? 
@@ -2407,6 +2444,7 @@ glade_eprop_text_create_input (GladeEditorProperty *eprop)
                                       GTK_POLICY_AUTOMATIC);
       gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (swindow),
                                            GTK_SHADOW_IN);
+      remove_scroll_events (swindow);
 
       eprop_text->text_entry = gtk_text_view_new ();
       gtk_scrollable_set_hscroll_policy (GTK_SCROLLABLE (eprop_text->text_entry), GTK_SCROLL_MINIMUM);