tdf#90694 reset group area listeners when splitting group

Change-Id: Ib3e85e1f7e12447fc2998711663ea1e9d1b322e5
(cherry picked from commit 2f6a0685)

sc/source/core/tool/sharedformula.cxx

@@ -52,6 +52,17 @@ void SharedFormulaUtil::splitFormulaCellGroup(const CellStoreType::position_type
         xGroup2->mpCode = xGroup->mpCode->Clone();
     }
 
+#if USE_FORMULA_GROUP_LISTENER
+    // At least group area listeners will have to be adapted. As long as
+    // there's no update mechanism and no separated handling of group area and
+    // other listeners, all listeners of this group's top cell are to be reset.
+    if (nLength2)
+    {
+        rTop.EndListeningTo( rTop.GetDocument(), NULL, ScAddress( ScAddress::UNINITIALIZED));
+        rTop.SetNeedsListening(true);
+    }
+#endif
+
     xGroup->mnLength = nRow - xGroup->mpTopCell->aPos.Row();
     if (xGroup->mnLength == 1)
     {