[This is preliminary documentation and subject to change.]
The Handler is notified through this event when a modal dialog wants to create a child.
Handler.
A string, the name of the new dialog.
None.
The Handler keeps the present dialog and creates the new one with the name indicated in the argument, placing it on top of the old one.
A PushButton control on a modal dialog is tied to this event in the ControlEvent table to create a child dialog, like a "Are you sure you want to cancel" dialog.