Drop uneeded render filter idea

piker/ui/_fsp.py

@@ -782,15 +782,12 @@ async def open_vlm_displays(
             ) -> None:
                 for name in names:
 
-                    render = False
-
                     if 'dark' in name:
                         color = dark_vlm_color
                     elif 'rate' in name:
                         color = vlm_color
                     else:
                         color = 'bracket'
-                        render = True
 
                     curve, _ = chart.draw_curve(
                         name=name,
@@ -808,7 +805,6 @@ async def open_vlm_displays(
                     # since only a placeholder of `None` is entered in
                     # ``.draw_curve()``.
                     flow = chart._flows[name]
-                    # flow.render = render
                     assert flow.plot is pi
 
             chart_curves(