The function
interface-visible-p
returns
nil
if
An error is signalled if pane is not a CAPI pane (that is, it is not an instance of a subclass of element, collection or pinboard-object).
Otherwise
interface-visible-p
returns
t
.
Note: On Microsoft Windows,
interface-visible-p
may return
t
even though the interface is entirely obscured by another window.