Fix crash undoing cut when left part was selected

src/timeline2/model/groupsmodel.cpp

@@ -148,6 +148,7 @@ Fun GroupsModel::destructGroupItem_lambda(int id)
         removeFromGroup(id);
         auto ptr = m_parent.lock();
         if (!ptr) Q_ASSERT(false);
+        ptr->clearGroupSelectionOnDelete(id);
         for (int child : m_downLink[id]) {
             m_upLink[child] = -1;
             QModelIndex ix;

src/timeline2/model/timelinefunctions.cpp

@@ -266,7 +266,7 @@ bool TimelineFunctions::requestClipCut(const std::shared_ptr<TimelineItemModel>
         int newClip = timeline->getClipByPosition(trackToSelect, position);
         if (newClip > -1) {
             timeline->requestSetSelection({newClip});
-            }
+        }
     }
     return count > 0;
 }   

src/timeline2/model/timelinemodel.cpp

@@ -4878,6 +4878,15 @@ void TimelineModel::requestClearSelection(bool onDeletion, Fun &undo, Fun &redo)
     }
 }
 
+void TimelineModel::clearGroupSelectionOnDelete(int gid)
+{
+    READ_LOCK();
+    if (gid == m_currentSelection) {
+        requestClearSelection(true);
+    }
+}
+
+
 std::unordered_set<int> TimelineModel::getCurrentSelection() const
 {
     READ_LOCK();

src/timeline2/model/timelinemodel.hpp

@@ -689,6 +689,11 @@ public:
         @param onDeletion is true when the selection is cleared as a result of a deletion
      */
     Q_INVOKABLE bool requestClearSelection(bool onDeletion = false);
+
+    /** @brief On group deletion, ensure the group was not selected, clear selection otherwise
+        @param gid The group id
+     */
+    void clearGroupSelectionOnDelete(int gid);
     // same function with undo/redo accumulation
     void requestClearSelection(bool onDeletion, Fun &undo, Fun &redo);