bindings: add a mechanism to prevent binding activation during drag

libs/gtkmm2ext/bindings.cc

@@ -46,6 +46,7 @@ using namespace PBD;
 
 list<Bindings*> Bindings::bindings; /* global. Gulp */
 PBD::Signal1<void,Bindings*> Bindings::BindingsChanged;
+int Bindings::_drag_active = 0;
 
 template <typename IteratorValueType>
 struct ActionNameRegistered
@@ -492,6 +493,12 @@ Bindings::activate (KeyboardKey kb, Operation op)
 		action = ActionManager::get_action (k->second.action_name, false);
 	}
 
+	/* bindings cannot be used during drags */
+
+	if (_drag_active) {
+		return true;
+	}
+
 	if (action) {
 		/* lets do it ... */
 		if (action->get_sensitive()) {

libs/gtkmm2ext/gtkmm2ext/bindings.h

@@ -167,6 +167,15 @@ class LIBGTKMM2EXT_API Bindings {
 
 	static PBD::Signal1<void,Bindings*> BindingsChanged;
 
+	struct DragsBlockBindings {
+		DragsBlockBindings() { Bindings::_drag_active++; }
+		~DragsBlockBindings() {
+			if (Bindings::_drag_active--) {
+				Bindings::_drag_active--;
+			}
+		}
+	};
+
   private:
 	std::string  _name;
 	KeybindingMap press_bindings;
@@ -197,6 +206,8 @@ class LIBGTKMM2EXT_API Bindings {
 	 */
 	static std::string ardour_action_name (Glib::RefPtr<Gtk::Action>);
 
+	static int _drag_active;
+	friend struct DragsBlockBindings;
 };
 
 } // namespace