viewport: mark rendered

src/fresnelrenderer.pas

@@ -65,12 +65,12 @@ begin
   LNode:=TSimpleFresnelLayoutNode(El.LayoutNode);
   if LNode.SkipRendering then exit;
 
+  El.Rendered:=true;
   if (El is TFresnelViewport) then
   begin
     aLeft:=0;
     aTop:=0;
   end else begin
-    El.Rendered:=true;
     aLeft:=El.GetRenderedCSSLength(fcaLeft,false);
     aTop:=El.GetRenderedCSSLength(fcaTop,false);