Popups are widgets which can be placed on top of the application.       Example       Here is a little example of how to use the widget.       <pre class='javascript'>    var button = new qx.ui.form.Button("Open Popup #1");    var popup = new qx.ui.popup.Popup(new qx.ui.layout.Canvas()).set({      backgroundColor: "#FFFAD3",      padding: [2, 4],      offset : 3,      offsetBottom : 20    });       popup.add(new qx.ui.basic.Atom("Hello World #1", "icon32appsmedia-photo-album.png"));       button.addListener("execute", function(e)    {      popup.placeToMouse(e);      popup.show();    }, this);    <pre>       This example creates a ToolTip and assigns it to a button. When the user hovers the    button the tooltip is shown.       External Documentation       <a href='http:manual.qooxdoo.org${qxversion}pageswidgetpopup.html' target='_blank'>    Documentation of this widget in the qooxdoo manual.<a>