Something wrong with Search box

On this site I have a JQuery powered search function (the lens button in the menu), when I click on it the search button opens but the close button does not work, how can I fix that?

The problem is that the div#header has a z-index of 999 and overlaps the closing button. Just remove the z-index there (all.css: line 108).
It would also be helpful to change the element of the closing button as well as the ok button from div to a(nchor) and to add a “:hover{ cursor: pointer;}” for these elements to mark them as clickable. But that is just a matter of usability.