diff --git a/components/tachart/tacustomseries.pas b/components/tachart/tacustomseries.pas
index d15280f37d..b352f8e347 100644
--- a/components/tachart/tacustomseries.pas
+++ b/components/tachart/tacustomseries.pas
@@ -1427,7 +1427,7 @@ begin
     lmpNegative: isNeg := true;
     lmpInside: isNeg := Source[AIndex]^.Y >= ref;
   end;
-  if isRotated and (ParentChart.IsRightToLeft xor GetAxisY.Inverted) then
+  if (isRotated and ParentChart.IsRightToLeft) xor GetAxisY.Inverted then
     isNeg := not isNeg;
   Result := DIR[IsRotated, isNeg];
 end;