diff -r 000000000000 -r 6474c204b198 toolkit/components/thumbnails/test/browser_thumbnails_bug727765.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/thumbnails/test/browser_thumbnails_bug727765.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,20 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const URL = "http://mochi.test:8888/browser/toolkit/components/thumbnails/" +
+            "test/background_red_scroll.html";
+
+// Test for black borders caused by scrollbars.
+function runTests() {
+  // Create a tab with a page with a red background and scrollbars.
+  yield addTab(URL);
+  yield captureAndCheckColor(255, 0, 0, "we have a red thumbnail");
+
+  // Check the thumbnail color of the bottom right pixel.
+  yield whenFileExists(URL);
+  yield retrieveImageDataForURL(URL, function (aData) {
+    let [r, g, b] = [].slice.call(aData, -4);
+    is("" + [r,g,b], "255,0,0", "we have a red thumbnail");
+    next();
+  });
+}