Now I want to squish the sprite a little bit, so I select the GO and change scale.x to 50. This has no effect and the sprite looks the same as it did before. And indeed - if I quit Defold and open the project again, this change will be undone.
But when editing just the sub_collection, you can’t see anything else. I ran into this because I wanted to make my outline a bit tidier, so I put interactive objects into a sub-collection and had the tilemap which contains the basic level geometry elsewhere, but this would make it tricky to place the objects in the right places.