How to mask something with linear gradient backround

[Luis30641577fdpo]

How can I simulate the disappearing behind the search bar, when someone scrolls with this type of backround colour? I used to do this with a fixed position rectangle in one colour, but this is not possible here.

[Kenneth Kawamoto]

Do you mean you want the thumbnails to scroll up underneath the search bar?

[Ares Hovhannesyan]

IMHO the task is to disappear scroll object when they scrolling under search bar

[Kenneth Kawamoto]

If the gradient has to scroll too then that's difficult