diff -r 000000000000 -r 6474c204b198 toolkit/themes/windows/global/customizeToolbar.css
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/themes/windows/global/customizeToolbar.css	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,23 @@
+/* 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/. */
+
+window,
+dialog {
+  padding: 6px;
+}
+
+#instructions {
+  font-weight: bold;
+  font-size: larger;
+}
+
+#palette-box {
+  -moz-appearance: listbox;
+  margin: 0 0 10px;
+}
+
+#palette-box > toolbarpaletteitem {
+  padding: 8px 2px;
+  margin: 0 8px;
+}