update timeline after delete function

timeline/sequence.h

@@ -120,6 +120,8 @@ public:
   int save_id;
 
   QVector<Marker> markers;
+signals:
+  void Changed();
 private:
   QVector<TrackList*> track_lists_;
 

ui/focusfilter.cpp

@@ -206,9 +206,12 @@ void FocusFilter::delete_function() {
     panel_graph_editor->delete_selected_keys();
   } else {
     Sequence* top_sequence = Timeline::GetTopSequence().get();
-    ComboAction* ca = new ComboAction();
-    top_sequence->DeleteAreas(ca, top_sequence->Selections(), true);
-    olive::undo_stack.push(ca);
+    if (top_sequence != nullptr) {
+      ComboAction* ca = new ComboAction();
+      top_sequence->DeleteAreas(ca, top_sequence->Selections(), true);
+      olive::undo_stack.push(ca);
+      Timeline::GetTopTimeline()->repaint_timeline();
+    }
   }
 }
 

undo/undo.cpp

@@ -270,8 +270,9 @@ void ModifyTransitionCommand::doRedo() {
   transition_ref_->set_length(new_length_);
 }
 
-DeleteTransitionCommand::DeleteTransitionCommand(TransitionPtr t) {
-  transition_ref_ = t;
+DeleteTransitionCommand::DeleteTransitionCommand(TransitionPtr t) :
+  transition_ref_(t)
+{
 }
 
 void DeleteTransitionCommand::doUndo() {