diff -r 000000000000 -r 6474c204b198 browser/themes/windows/devtools/webconsole.css
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/themes/windows/devtools/webconsole.css	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,14 @@
+/* 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/. */
+
+%include ../../shared/devtools/webconsole.inc.css
+
+/*
+ * This hardcoded width likely due to a toolkit Windows specific bug.
+ * See http://hg.mozilla.org/mozilla-central/annotate/f38d6df93cad/toolkit/themes/winstripe/global/textbox-aero.css#l7
+ */
+
+.hud-filter-box {
+  width: 200px;
+}