Denotes that the object is a transient window or frame associated with another onscreen object.
Similar to ATSPI_TOOLTIP_FOR, but more general. Useful for windows which are technically toplevels but which, for one or
more reasons, do not explicitly cause their associated window to lose 'window focus'. Creation of an ATSPI_ROLE_WINDOW object
with the ATSPI_RELATION_POPUP_FOR relation usually requires some presentation action on the part of assistive technology
clients, even though the previous toplevel ATSPI_ROLE_FRAME object may still be the active window.