How can I make the MediaWiki search field dynamically wider?

Question

At Wikipedia, the search field (when located on the left, in the sidebar) gets dynamically wider if the suggested page name is too wide for the default search field.

Does anyone know how to switch this on (or how it might be switched off)? I've checked LocalSettings.php, MediaWiki:Common.css and MediaWiki:Common.js but cannot find anything.

Clarification: I'm looking for a dynamic change (depending on page width), not structurally increasing the sidebar width.

Answer 1

when using the new Vector skin, install the Vector extension and add this to your LocalSettings.php (after including the extension files):

$wgVectorFeatures['expandablesearch']['global'] = true;

This would expand the search box dynamically when it is focused on, but this is only a functionality of the Vector skin.