diff --git a/toolkit/mozapps/extensions/content/extensions.xul b/toolkit/mozapps/extensions/content/extensions.xul
index 02f7478036e9..df4661ada915 100644
--- a/toolkit/mozapps/extensions/content/extensions.xul
+++ b/toolkit/mozapps/extensions/content/extensions.xul
@@ -200,7 +200,7 @@
                   command="cmd_resetAddonAutoUpdate"/>
       </menupopup>
     </toolbarbutton>
-    <textbox id="header-search" type="search" searchbutton="true"
+    <textbox id="header-search" type="search" searchbutton="true" size="35"
              placeholder="&search.placeholder;"/>
   </hbox>