Last watch function

[koover]

Don't know if this is even the right place to post this, so I'm sure a Mod will move it if it isn't.

Pretty basic question
How do you use the last watched function when you are in your profile area?

It seems the only time this populates, is when I input the last new movie I bought that was entered into my collection. Am I missing something so easy that the answer will be, duh?

And yes, I did do a search but didn't see anything.