Thread:Project:Support desk/Add HTML to sidebar

Hello! I'm trying to add a custom search box to the sidebar of my MediaWiki 1.21.1 installation. The goal is to type in a page revision ID, press go, and have the browser navigate to that page.

I have a working HTML form:

...and I've tried to add it to the sidebar by editing the Mediawiki:Sidebar special page using  tags, but the search box doesn't appear.

Is there any way to do this?

Thanks for your time!