Cleans the search filter.
@private
function cleanFilter() {
        sbSearch.reset();
        if (!templateOpts.sidebar.enabled || !$sidebarNodes) return;

        setFilterBtnStates();

        if ($txtSearch) $txtSearch.val('');
        $sidebarNodes.removeClass('hidden');
        if ($btnClean) $btnClean.hide();
        $('.toolbar-buttons > span').css('color', '#fff');
        // show back the chevrons within the sidebar symbols.
        $('.chevron').show();
        // reset outline back to initial value
        setTimeout(function () {
            setSidebarNodesOutline(templateOpts.sidebar.outline);
            if ($txtSearch) $txtSearch.focus();
        }, 100); // with a little delay
        isFilterActive = false;
    }