Close a loophole in AUI_CONTROL whereby you could cause havoc by specifying an invalid parent control ID # when creating a control. Particularly nasty was the case where you specified the control as its own parent, or one of its children as its parent. Such attempts will now either be detected when you try to create the control (in which case AUI_CONTROL will return status -13 for invalid parent), or when controls are being scanned for various purposes (in which case a warning will be sent to the debug window).
