klyn.gui.windows.DockPane.collapseButtonContains
method

    public collapseButtonContains(x as Int, y as Int) as Boolean:

Description

Returns true when `x`, `y` hits the pane collapse button.

Native backends and parent workspaces use this to route close gestures reliably even when hit-testing targets a nested child widget.

    if pane.collapseButtonContains(mouseX, mouseY):
    pane.collapse()