Chrome Developer Tools - How to lock css classlist?

I need to inspect a search bar. The search bar is initially hidden and only shows after clicking on the search icon.

However, if I click on my developer tools then the search bar dissapears again... If the search box should appear, then a class named active is added. So I tried to add the class manually but if I inspect other elements, then the active class is removed again...

Is there a way to lock the classlist? I could write a javascript interval method which sets the classlist, as a workaround.

e.g.

setInterval(function() {
    jQuery("#debug")[0].classList = "label icon faSearch active";
}, 1000 );

But is there an easier way?