ReadonlypointerThe click that caused a "pointer" activation; null for a keyboard or
programmatic one.
There is deliberately no matching keyEvent: a key activation's cause is
already fully described by "Enter or Space on the focused control" (see
Button), and a listener that needs the keystroke itself can read it from
its own keydown listener, which fires on the same node first.
ReadonlysourceWhether a pointer, a key, or an explicit activate() call caused this.
ReadonlywidgetThe activated widget — always the emitter.
Payload of the
uiactivateevent (§72 click → §73 button activation).