diff -r 000000000000 -r 6474c204b198 browser/themes/windows/devtools/inspector.css
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/themes/windows/devtools/inspector.css	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,26 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* 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/. */
+
+#inspector-searchbox {
+  transition-property: max-width, -moz-padding-end, -moz-padding-start;
+  transition-duration: 250ms;
+  transition-timing-function: ease;
+}
+
+#inspector-searchbox:not([focused]):not([filled]) > .textbox-input-box {
+  overflow: hidden;
+}
+
+#inspector-searchbox:not([focused]):not([filled]) {
+  max-width: 20px !important;
+  -moz-padding-end: 6px;
+  -moz-padding-start: 22px;
+  background-position: 8px center, top left, top left;
+}
+
+#inspector-searchbox[focused],
+#inspector-searchbox[filled] {
+  max-width: 200px !important;
+}