Currently clicking Wiki is a top-level click which selects the Wiki page, with all page settings left unaltered - ie last Topic displayed and search text unchanged.

Clicking on [clear] clears the search text but will not take you back to the "Welcome" page, instead retains the currently displayed topic.

OK, you think that clicking "Wiki" should clear the search text. But should it also reset the page to "Welcome"? I'm not sure ...