Do I absolutely need this door handle piece?

What is this thing? It goes on the inside of the door and attaches to the handle. A few weeks ago I heard something drop down the inside of the door when I closed it. Pulled the inside door panel last night and found this sitting at the bottom.

My passenger side doesnt even have one. /ubbthreads/images/graemlins/uhh.gif

 

[Terry Posten]

It holds the "thumb cap" on.

 

Thanks!