Gets and sets the expanded state of an item in a tree-view.
The generic function
tree-view-expanded-p
is the predicate for whether
item
is expanded in
tree-view
. If item is not in
tree-view
, the function returns
nil
.
(setf tree-view-expanded-p)
sets the expanded state of
item
in
tree-view
to
on
. If
item
is not in
tree-view
, the function does nothing.