Hi,
It is because the extension of search module requires flexibleVM2Global.css in order to run, (which comes with our VM Template) and this CSS file is loaded only in Virtuemart-related pages. When you go out to any other component's page (for example; com_contents which is used to show "articles" in your joomla such as your contact page...) then since this CSS file is missing, the expansion module fails to work.
There is an easy patch for it.
Open this PHP file:
www.thebatcave.me/kozihaus/templates/yoo_tasty/html/mod_virtuemart_search/default.php
and RIGHT AFTER THIS LINE:
$doc->addScriptDeclaration($jsFlexible);
ADD THIS LINE:
include_once dirname(__FILE__) . '/../com_virtuemart/assets/includes/flexibleMartGlobal.php';
And should be good to go. If doesn't work, please let me know.