Question

Just want to remove highlight class before applying class again on other elements. Reseting the selected items. How?

removeClass not working in the below code.

$("#toggleCustom").on("click", function () {
    var $this = $(this),
    $domtree = $this.parents('div.section').find('div.domtree'),
    query = $this.prev().val();
    //$domtree.removeClass('highlight').animate({ marginLeft: 0 }, 'fast');
    $domtree.find(query).addClass('highlight').animate({ marginLeft: 10 }, 'fast');
});

Answer 1

removeClass acts only on the elements in the matched set of the jQuery instance you call it on; not on descendants of that set. From your code:

$domtree.find(query).addClass('highlight').animate({ marginLeft: 10 }, 'fast');

…it looks like the class is actually applied to descendant element(s) (e.g., ones matching the selector in query).

You can find and remove it on all descendants like this:

$domtree.find(".highlight").removeClass("highlight");