Why does not open AlloyUI modal dialog in the second time?

I am trying to load external URL into modal AlloyUI dialog in Liferay Portal. If I open dialog at the first time the contents are showing but at the second time the contents are not showing. If refresh the page its showing.

This is my function:

Liferay.provide(
    window,
    'openModal',
    function(title, url) {
        var A = AUI();
        var width = 800;

        var modal = Liferay.Util.Window.getWindow({
            dialog: {
                centered: true,
                constrain2view: true,
                modal: true,
                resizable: false,
                height: 650,
                width: width,
                //destroyOnClose: true,
                destroyOnHide: true,
                toolbars: {
                    footer: [
                        {
                            label: 'Close',
                            cssClass: 'btn-link pull-right',
                            on: {
                                click: function() {
                                    modal.hide();
                                }
                            }
                        }
                    ]
                }
            },
            closeOnOutsideClick: true,
            id:'test-dialog',
            title: title
        }).plug(A.Plugin.IO, {
            uri: url,
            on: {
                success: function(event) {
                    console.log("success");
                },
                complete: function(event) {
                    console.log("complete");
                },
                start: function(event) {
                    console.log("start");
                },
                failure: function(event) {
                    console.log("failure");
                }
            }
        }).render();
    }
);

The function is used in this link:

<a href="javascript:openModal('${title}','${url}');">Open dialog</a>

When I open dialog at the second time I get this error:

Cannot read property 'Window' of undefined

Resolved by using A.Plugin.DialogIframe module insted of A.Plugin.IO