Gtk.TreeView::test-collapse-row

function callback(tree_view, iter:Gtk.TreeIter, path:Gtk.TreePath, ):Boolean;

The given row is about to be collapsed (hide its children nodes). Use this signal if you need to control the collapsibility of individual rows.

tree_view

instance of Gtk.TreeView that is emitting the signal

iter

the tree iter of the row to collapse

path

a tree path that points to the row

Returns

false to allow collapsing, true to reject