diff -r 000000000000 -r 6474c204b198 browser/themes/linux/engineManager.css
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/themes/linux/engineManager.css	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,16 @@
+%if 0
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+%endif
+
+#engineList treechildren::-moz-tree-image(engineName) {
+  -moz-margin-end: 4px;
+  -moz-margin-start: 1px;
+  width: 16px;
+  height: 16px;
+}
+
+#engineList treechildren::-moz-tree-row {
+  height: 20px;
+}