public function show(realParent:Sprite,
                     displayParent:Sprite = null,
                     closeHandler:Function = null,
                     moduleFactory:IFlexModuleFactory = null):Dialog {

    // Get the parent ...
    // If none is set, use the top-level-application.
    if (!displayParent) {
        var sm:ISystemManager = ISystemManager(FlexGlobals.topLevelApplication.systemManager);
        // no types so no dependencies
        var mp:Object = sm.getImplementation("mx.managers.IMarshallPlanSystemManager");
        if (mp && mp.useSWFBridge())
            displayParent = Sprite(sm.getSandboxRoot());
        else
            displayParent = Sprite(FlexGlobals.topLevelApplication);
    }

    // Register for close-events, making sure the pop-up is closed.
    if (closeHandler != null) {
        this.addEventListener(CloseEvent.CLOSE, closeHandler);
    }

    // Setting a module factory allows the correct embedded font to be found.
    if (moduleFactory) {
        this.moduleFactory = moduleFactory;
    } else if (realParent is IFlexModule) {
        this.moduleFactory = IFlexModule(realParent).moduleFactory;
    } else {
        if (realParent is IFlexModuleFactory) {
            this.moduleFactory = IFlexModuleFactory(realParent);
        } else {
            this.moduleFactory = FlexGlobals.topLevelApplication.moduleFactory;
        }

        // also set document if parent isn't a UIComponent
        if (!parent is UIComponent) {
            this.document = FlexGlobals.topLevelApplication.document;
        }
    }

    // Make the dialog center itself relative to the parent.
    PopUpManager.addPopUp(this, displayParent, true);
    PopUpManager.centerPopUp(this);

    return this;
}