WidgetInvoker: do not handle the clicked signal when there is no user interaction, part of SL #4307

There are cases where there is no user interaction but we do
receive a clicked signal: in the clipboard we do have
GtkRadioToolButton which are derived from the GtkToggleToolButton [1].

The 'clicked' signal is emitted when the 'active' property
changes [2]. We use the 'active' property to indicate the
current active clipping. In the Invoker we do check now
if the event originated a user interaction or if it was
generated due to a for example a property change.

[1] http://developer.gnome.org/gtk3/3.4/GtkToggleToolButton.html
[2] http://developer.gnome.org/gtk3/3.4/GtkToggleToolButton.html#GtkToggleToolButton--active

Signed-off-by: Simon Schampijer <simon@laptop.org>
Reviewed-by: Carlos Garnacho <carlos@lanedo.com>
Acked-by: Manuel Quiñones <manuq@laptop.org>

src/sugar3/graphics/palettewindow.py

@@ -1155,6 +1155,18 @@ class WidgetInvoker(Invoker):
         return False
 
     def __click_event_cb(self, button):
+        event = Gtk.get_current_event()
+        if not event:
+            # not an event from a user interaction, this can be when
+            # the clicked event is emitted on a 'active' property
+            # change of ToggleToolButton for example
+            return
+        if event and button != Gtk.get_event_widget(event):
+            # another special case for the ToggleToolButton: this handles
+            # the case where we select an item and the active property
+            # of the other one changes to 'False'
+            return
+
         if self.props.lock_palette and not self.locked:
             self.locked = True
             if hasattr(self.parent, 'set_expanded'):