The predicate for whether the interface containing a pane is visible.
capi
interface-visible-p pane => visiblep
| pane⇩ | 
A CAPI pane. | 
| visiblep | 
A boolean. | 
The function interface-visible-p returns nil if one of the following is true:
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.
On Microsoft Windows, interface-visible-p may return t even though the interface is entirely obscured by another window.
CAPI User Guide and Reference Manual (Unix version) - 01 Dec 2021 19:32:42