When creating a PopupObject, the first and only argument passed is a string indicating what popup type the popup should be. This does two things:
Specifies the CSS class name of the popup node for styling (the default is "popup-object").
Allows you to have more than one popup open at a time. Each popup type can have one member at a time; when creating a new popup any existing popup of that type (and only of that type) will first be destroyed.
Below are multiple popup node triggers; you should be able to have one of each type open at once.