If you want the button to land on a "Play Movie" button instead of itself after pressing enter, you must set the link of the subtitle toggle button to that "Play Movie" button, and also make sure you configure the toggle of the subtitle in the "Specify Link" window.
To do this all in one step, select the subtitle toggle button, then in the link field of the properties, click on the drop-down and select "Specify Link". Once the window pops up, choose the same menu you are on and the "Play Movie" button you want it to land on, then configure the subtitle at the bottom to the appropriate setting.
Jon Geddes
http://www.precomposed.com