The function pane-has-focus-p
is the predicate for whether
pane
currently has the input focus.
On Motif, pane-has-focus-p
cannot be used in menu functions such as the
enabled-function
or
popup-callback
of a menu item. It will always return nil,
because the focus is on the menu button when the user clicks on it.
CAPI User Guide and Reference Manual (Macintosh version) - 3 Aug 2017