Move mask inside precomposition in After Effects?

Question

I have a movie in after effects. I created a color key, applied a simple choker and then added a mask.

When I move the mask point, it is offset by the simple choker value - so I thought I would precompose the whole thing, so I can apply a second mask that isn't affected by the simple choker.

However, when I do that - the mask that was applied to the movie is not moved "inside" the precomp. It gets moved outside the precomp, and is still affected by the simple choker.

How do I solve this?

Answer 1

So, it was a simple thing:

Instead of "Leave all attributes" when pre-composing, I needed to switch to "Move all attributes".