




The function docking-layout-pane-visible-p returns a boolean indicating whether 
pane
 is currently visible in the Docking Group of 
docking-layout
. 
pane
 may be docked in any member of the Docking Group, or undocked.
(setf docking-layout-pane-visible-p) may be used to change the visibility of pane in 
docking-layout
 only when 
pane
 is dockable in the Docking Group of 
docking-layout
, that is, it was added to the 
items
 of any of the docking-layouts in the group.
CAPI User Guide and Reference Manual (Macintosh version) - 3 Aug 2017