Word for hiding "all other layers" in graphics design

Solution 1:

I suggest mask. Lexico has

mask
NOUN

6 Photography
A piece of material such as card used to cover a part of an image that is not required when exposing a print.

The entry does say photography but one of its example usage sentences is

The Unsharp Mask is an old photography trick that has become available to ‘the common man’ through the introduction of digital editing tools.

Mask is also used as a verb.