--- a/toolkit/mozapps/extensions/content/extensions.xul
+++ b/toolkit/mozapps/extensions/content/extensions.xul
@@ -246,17 +246,17 @@
                 <menuitem id="utils-resetAddonUpdatesToManual"
                           label="&updates.resetUpdatesToManual.label;"
                           accesskey="&updates.resetUpdatesToManual.accesskey;"
                           command="cmd_resetAddonAutoUpdate"/>
               </menupopup>
             </toolbarbutton>
             <textbox id="header-search" type="search" searchbutton="true"
                      searchbuttonlabel="&search.buttonlabel;"
-                     placeholder="&search.placeholder2;"/>
+                     placeholder="&search.placeholder2;" maxlength="100"/>
           </hbox>
 
           <deck id="headered-views-content" flex="1" selectedIndex="0">
             <!-- list view -->
             <vbox id="list-view" flex="1" class="view-pane" align="stretch" tabindex="0">
               <!-- info UI for add-ons that have been disabled for being unsigned -->
               <vbox id="disabled-unsigned-addons-info" hidden="true">
                 <label id="disabled-unsigned-addons-heading" value="&disabledUnsigned.heading;"/>