Fix crash on exit when a mix is selected

src/timeline2/view/timelinecontroller.cpp

@@ -98,6 +98,8 @@ void TimelineController::prepareClose()
     disconnect(m_model.get(), &TimelineModel::selectionChanged, this, &TimelineController::selectionChanged);
     disconnect(this, &TimelineController::videoTargetChanged, this, &TimelineController::updateVideoTarget);
     disconnect(this, &TimelineController::audioTargetChanged, this, &TimelineController::updateAudioTarget);
+    disconnect(m_model.get(), &TimelineModel::selectedMixChanged, this, &TimelineController::showMixModel);
+    disconnect(m_model.get(), &TimelineModel::selectedMixChanged, this, &TimelineController::selectedMixChanged);
     m_ready = false;
     m_root = nullptr;
     // Delete timeline preview before resetting model so that removing clips from timeline doesn't invalidate
@@ -133,10 +135,8 @@ void TimelineController::setModel(std::shared_ptr<TimelineItemModel> model)
     connect(m_model.get(), &TimelineModel::invalidateZone, this, &TimelineController::invalidateZone, Qt::DirectConnection);
     connect(m_model.get(), &TimelineModel::durationUpdated, this, &TimelineController::checkDuration);
     connect(m_model.get(), &TimelineModel::selectionChanged, this, &TimelineController::selectionChanged);
-    connect(m_model.get(), &TimelineModel::selectedMixChanged, [this] (int cid, const std::shared_ptr<AssetParameterModel> &asset) {
-        emit showMixModel(cid, asset);
-        emit selectedMixChanged();
-    });
+    connect(m_model.get(), &TimelineModel::selectedMixChanged, this, &TimelineController::showMixModel);
+    connect(m_model.get(), &TimelineModel::selectedMixChanged, this, &TimelineController::selectedMixChanged);
     connect(m_model.get(), &TimelineModel::checkTrackDeletion, this, &TimelineController::checkTrackDeletion, Qt::DirectConnection);
 }