Bug: Disabled MenuItem still receive events

[jhickman]

Disabled menu items appear to have the style applied, but will still execute the click handlers.

sample code:

Button.create("click")
  .setDropMenu(Menu.create()
    .appendChild(MenuItem.create("Test")
      .disable()
      .addClickListener(evt -> DomGlobal.alert("fail"))
    )
  )

[vegegoku]

Trying to reproduce this and it seems the clickListeners does not work after disable but Selection listeners still working.

[jhickman]

fix LGTM