Resolves: tdf#120013 tdf#123714 split-off group or single cell needs listening

Change-Id: Ic511f618e9dde2288491c01cfcd889970fd6e4e5
Reviewed-on: https://gerrit.libreoffice.org/69066Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Jenkins

sc/source/core/tool/sharedformula.cxx

@@ -71,6 +71,9 @@ bool SharedFormulaUtil::splitFormulaCellGroup(const CellStoreType::position_type
         else
             rPrevTop.EndListeningTo( rPrevTop.GetDocument(), nullptr, ScAddress( ScAddress::UNINITIALIZED));
         rPrevTop.SetNeedsListening(true);
+
+        // The new group or remaining single cell needs a new listening.
+        rTop.SetNeedsListening(true);
     }
 #endif