Autoflatten Strokes/Fills?

I know that TBS has a “Draw Top Layer” feature that flattens all strokes of the same color. However, it also causes new colors to erase segments of others once you’ve deleted them. As for fills, they always stay separate.

Is there some way to flatten drawings of the same color like I you can supposedly do in Animate while keeping the colors intact from one another?

This is something I know Flash does automatically.

I discovered that, similar to Flash, using the pencil tool to separate flats from shades when colors works with “Draw Top Layer” because the pencil tool won’t mess up the drawing. Still would be nice to have a “draw behind” feature like in Animate.

I think this is normal to cut the (bottom) line when (top) line moved when they are using different color after flatten on brush tool since pencil tool does not have contour line and should not be cut after flatten. And the feature something like ‘select by color’ or ‘draw behind’ feature in Animate would not help to intact the ‘brush’ line if the brush line using different color is on top once they are flattened. Beside ‘flatten’ draw behind is good feature in Animate family which does not have in Toon Boom Studio as far as I know.