     tile_data = e.target.tile_data
     tile_data.img = e.target
     tile_data.current = true
-    @mget('tile_source').tiles[tile_data.cache_key] = tile_data
+    tile_data.loaded = true
     @request_render()
 
   _on_tile_cache_load: (e) =>
     tile_data = e.target.tile_data
     tile_data.img = e.target
-    @mget('tile_source').tiles[tile_data.cache_key] = tile_data
+    tile_data.loaded = true
 
   _on_tile_error: (e) =>
     return ''

            for c in children
              [cx, cy, cz, cbounds] = c
              child_key = @mget('tile_source').tile_xyz_to_key(cx, cy, cz)
              if child_key of @mget('tile_source').tiles
                children.push(child_key)

          need_load.push(t)

    # draw stand-in parents ----------

{logger} = require "../../common/logging"

class TileRendererView extends PlotWidget

  get_extent: () ->
    return [@x_range.get('start'), @y_range.get('start'), @x_range.get('end'), @y_range.get('end')]

