_stopDocumentScrolling: function () {
                var that = this;
                var containment = that.containment;
                if (containment && !that._isPinned) {
                    that._storeOverflowRule(containment);
                    containment.css(OVERFLOW, HIDDEN);
                    that.wrapper.css({
                        maxWidth: containment.innerWidth(),
                        maxHeight: containment.innerHeight()
                    });
                    return;
                }
                var $body = $('body');
                that._storeOverflowRule($body);
                $body.css(OVERFLOW, HIDDEN);
                // LSS: maintain scroll position when opening modal popup window
                var $html = $('html'),
                    scrollTop = $html.scrollTop();
                that._storeOverflowRule($html);
                $html.css(OVERFLOW, HIDDEN);
                // LSS: maintain scroll position when opening modal popup window
                $html.add($body).scrollTop(scrollTop);
            },
            _enableDocumentScrolling: function () {
                var that = this;
                var containment = that.containment;
                if (containment && !that._isPinned) {
                    that._restoreOverflowRule(containment);
                    that.wrapper.css({
                        maxWidth: containment.width,
                        maxHeight: containment.height
                    });
                    return;
                }
                that._restoreOverflowRule($(document.body));
                that._restoreOverflowRule($('html'));
            },
            _storeOverflowRule: function ($element) {
                if (this._isOverflowStored($element)) {
                    return;
                }
                var overflowRule = $element.get(0).style.overflow;
                if (typeof overflowRule === 'string') {
                    $element.data(DATADOCOVERFLOWRULE, overflowRule);
                    // LSS: maintain scroll position when opening modal popup window
                    $element.data('scrollTop', $element.scrollTop());
                }
            },
            _isOverflowStored: function ($element) {
                return typeof $element.data(DATADOCOVERFLOWRULE) === 'string';
            },
            _restoreOverflowRule: function ($element) {
                var overflowRule = $element.data(DATADOCOVERFLOWRULE);
                if (overflowRule !== null && overflowRule !== undefined) {
                    $element.css(OVERFLOW, overflowRule);
                    $element.removeData(DATADOCOVERFLOWRULE);
                    // LSS: maintain scroll position when opening modal popup window
                    var scrollTop = $element.data('scrollTop')
                    $element.scrollTop(scrollTop)
                    $element.removeData('scrollTop');
                } else {
                    $element.css(OVERFLOW, '');
                }
 },