on-activate

Called when a window is activated or deactivated. A top-level window is activated when the keyboard focus moves from outside the window to the window or one of its children. It is deactivated when the focus moves back out of the window.

The method's argument is #t when the window is activated, #f when it is deactivated.

• (send a-top-level-window on-activate active?) -> void
      active? : boolean