on-focus in drscheme:get/extend:base-interactions-canvas

Called when a window receives or loses the keyboard focus. If the argument is #t, the keyboard focus was received, otherwise it was lost.

Note that under X, keyboard focus can move to the menu bar when the user is selecting a menu item.

• (send a-drscheme:get/extend:base-interactions-canvas on-focus on?) -> void
     on? : boolean

  When the focus is on, calls make-searchable with this.