From 3fd4e571627a1d3fd9c8b8e489c11d508b4e608c Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Sat, 21 Jun 2014 02:23:59 -0600
Subject: [PATCH] Render a dummy highlight decoration to prevent artifacts

When the last highlight gets removed, we get a rendering artifact.
Always rendering an empty dummy at 0,0 ensures that never happens.
---
 src/editor-component.coffee | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/editor-component.coffee b/src/editor-component.coffee
index 7f475fb1b..f1d6ceaa6 100644
--- a/src/editor-component.coffee
+++ b/src/editor-component.coffee
@@ -12,6 +12,8 @@ ScrollbarComponent = require './scrollbar-component'
 ScrollbarCornerComponent = require './scrollbar-corner-component'
 SubscriberMixin = require './subscriber-mixin'
 
+DummyHighlightDecoration = {id: 'dummy', screenRange: new Range(new Point(0, 0), new Point(0, 0)), decorations: [{class: 'dummy'}]}
+
 module.exports =
 EditorComponent = React.createClass
   displayName: 'EditorComponent'
@@ -269,6 +271,12 @@ EditorComponent = React.createClass
           if editor.decorationMatchesType(decoration, 'highlight')
             filteredDecorations[markerId] ?= {id: markerId, screenRange: marker.getScreenRange(), decorations: []}
             filteredDecorations[markerId].decorations.push decoration
+
+    # At least in Chromium 31, removing the last highlight causes a rendering
+    # artifact where chunks of the lines disappear, so we always leave this
+    # dummy highlight in place to prevent that.
+    filteredDecorations['dummy'] = DummyHighlightDecoration
+
     filteredDecorations
 
   observeEditor: ->