Layer copy tool

This is a tool that uses the information from the lower layer it allows you to use any brush but it’s alpha is the alpha below it for example if you needed to create a seperate layer that had the same alpha but a different color you could easily accomplish this Just an idea.

Can you explain more about the use case leading to that feature wish?

We might of achieved a similar effect with the super selection stencil idea that you answered I think were cool,
Thanks again.