Fix track compositing duplicated on track insert/delete

src/timeline2/model/timelinefunctions.cpp

@@ -1073,6 +1073,7 @@ void TimelineFunctions::saveTimelineSelection(const std::shared_ptr<TimelineItem
             }
             t.set("always_active", 1);
             t.set("internal_added", 237);
+            t.set_tracks(isAudio ? lowerAudioTrack : lowerVideoTrack, ix);
             field->plant_transition(t, isAudio ? lowerAudioTrack : lowerVideoTrack, ix);
         }
         ix++;

src/timeline2/model/timelineitemmodel.cpp

@@ -567,13 +567,15 @@ void TimelineItemModel::buildTrackCompositing(bool rebuild)
         while (service != nullptr && service->is_valid()) {
             if (service->type() == transition_type) {
                 Mlt::Transition t((mlt_transition)service->get_service());
+                service.reset(service->producer());
                 if (t.get_int("internal_added") == 237) {
                     // remove all compositing transitions
                     field->disconnect_service(t);
                     t.disconnect_all_producers();
                 }
+            } else {
+                service.reset(service->producer());
             }
-            service.reset(service->producer());
         }
     }
     QString composite = TransitionsRepository::get()->getCompositingTransition();

src/timeline2/view/timelinecontroller.cpp

@@ -1704,14 +1704,16 @@ void TimelineController::switchCompositing(int mode)
     while ((service != nullptr) && service->is_valid()) {
         if (service->type() == transition_type) {
             Mlt::Transition t((mlt_transition)service->get_service());
+            service.reset(service->producer());
             QString serviceName = t.get("mlt_service");
             if (t.get_int("internal_added") == 237 && serviceName != QLatin1String("mix")) {
                 // remove all compositing transitions
                 field->disconnect_service(t);
                 t.disconnect_all_producers();
             }
+        } else {
+            service.reset(service->producer());
         }
-        service.reset(service->producer());
     }
     if (mode > 0) {
         const QString compositeGeometry =