diff --git a/lcl/include/treeview.inc b/lcl/include/treeview.inc
index 529d880a47..51db8d57fe 100644
--- a/lcl/include/treeview.inc
+++ b/lcl/include/treeview.inc
@@ -3384,6 +3384,7 @@ end;
 
 procedure TCustomTreeView.SetDefaultItemHeight(Value: integer);
 begin
+  if tvoAutoItemHeight in FOptions then exit;
   if Value<=0 then Value:=20;
   if Value=FDefItemHeight then exit;
   FDefItemHeight:=Value;