in changeset:   8253:cae1bbf2536b, replaced:

  self.renderError(e.args[0])

with:

   self.template = "search"
   self.write_html(self.renderContext())

self.template is "index" which tries to execute the search and fails over and over
again. By changing it to "search", I get the search page with the error and the
bad entry is displayed in the text input.

If the search was not generated from an alternate search page, the user is redirected
to the base search page. This might not allow the user to fix the problem (e.g. if
the search field is not present).

I think this is done for now. If we have somebody run into the alternate search page 
problem we can handle it then. A couple of ways might work:

  1) submit the page using an '@template=oktemplate|errortemplate' and change the
     core code to store that template info so I can use it when I handle the
     ExpressionError. This is probably the cleaner way to do it. Modifying
     the template element of the Client class to add oktemplate/errortemplate
     and parsing/setting them in determine_context().

  2) the search template can look for fields that an alternate search template
     handles and redirect the user by adding @template=altsearch to the url.
     This can be implemented in a tracker while 1 needs core code changes.