This might be because the view doesn't actually post the mouse event?

      const gfx::Point center = GetLocalBounds().CenterPoint();
      ui::MouseEvent press(ui::ET_MOUSE_PRESSED, center, center,
                           ui::EventTimeForNow(), ui::EF_LEFT_MOUSE_BUTTON,
                           ui::EF_LEFT_MOUSE_BUTTON);
      OnEvent(&press);
      ui::MouseEvent release(ui::ET_MOUSE_RELEASED, center, center,
                             ui::EventTimeForNow(), ui::EF_LEFT_MOUSE_BUTTON,
                             ui::EF_LEFT_MOUSE_BUTTON);
      OnEvent(&release);

I'm imagining that either Automation is picking the wrong handler for this action, or that the View class isn't properly finding the menu if it is open.

@dtseng, do you have any ideas of where I can go next?