What in the heck is this?

[PIMking]

I was doing a detailed cleaning my M&P9c and when I was removing the sear block this little block thing with one hole at the end and a small spring came off. I have no idea what it is or where it goes. Can anyone help me?

 

[PIMking]

Figured it out, it happens to be a thumb safety block on the sear.

That's where it's suppose to go.