     @lineDecorationsByScreenRow = {}
     @lineNumberDecorationsByScreenRow = {}
     @customGutterDecorationsByGutterName = {}
-    @blockDecorationsDimensions = new Map
+    @blockDecorationsDimensionsById = new Map
     @screenRowsToMeasure = []
     @transferMeasurementsToModel()
     @transferMeasurementsFromModel()

      @emitDidUpdateState()

  setBlockDecorationSize: (decoration, width, height) ->
    @blockDecorationsDimensions.set(decoration.id, {width, height})

    @shouldUpdateBlockDecorations = true
    @shouldUpdateVerticalScrollState = true

    for decoration in @model.getDecorations(type: "block")
      blockDecorations[decoration.id] = decoration

    @blockDecorationsDimensionsById.forEach (value, key) =>
      unless blockDecorations.hasOwnProperty(key)
        @blockDecorationsDimensionsById.delete(key)

    @shouldUpdateVerticalScrollState = true

