Let's search in namespace Mediawiki, without messing with preferences,
or not even being logged in.

One clicks the search button and arrives at
http://en.wikipedia.org/wiki/Special:Search?search=&fulltext=Search

Where he sees
http://en.wikipedia.org/wiki/Wikipedia:Searching
where it says

To search the other namespaces check or uncheck the tickboxes in
"Search in namespaces" box found at the bottom of a search results
page.

But if one has no results yet, there are no tickboxes.

Therefore
http://en.wikipedia.org/wiki/Special:Search?search=&fulltext=Search
should have the tickboxes, without requiring an extra search first
just to get them.

Version: 1.10.x
Severity: trivial