Horizontal Scroll issue (hiding images)

[Redcase Software]

I follow this demo for a horizontal scroll container. 

See the Pen WNjaxKp by GreenSock (@GreenSock) on CodePen

 

My demo is just a container with img elements inside that i want them to be full width, pin them, and start a horizontal scroll for each element. After that just scroll normally. Like the demo. 
But for some reason, when i start the horizontal scroll my elements are just hiding. I'm really struggling to figure out what is wrong here with no results.

Can anybody help me with this? I feel like it's something stupid.

Thanks in advance

See the Pen YzOKjYL by pmakos (@pmakos) on CodePen

[Redcase Software]

Okay, don't mind it. I had wrong selector in my css......