Keep scrolling tile around for mousewheel

src/tile-component.coffee

@@ -21,9 +21,13 @@ class TileComponent
     @screenRowsByLineId = {}
     @lineIdsByScreenRow = {}
     @domNode = document.createElement("div")
+    @domNode.addEventListener("mousewheel", @onMouseWheel)
     @domNode.style.position = "absolute"
     @domNode.classList.add("tile")
 
+  onMouseWheel: =>
+    @presenter.setScrollingTile(@id)
+
   getDomNode: ->
     @domNode