this is probably a bit tall order, so consider it more like a food for thought, however how hard do you think it would be to add layers to roassal?

Examples of layers could be

1 - background (grid),

2 - the visualized figures,

3 - selection highlights

4 - handles (moving handles, resize handles)

There are certain benefits like clearing all handles by simply replacing a layer with clear one, potential performance improvements and more. It would definitely require more thought but it might be interesting to consider in the coming years.

Cheers,

Peter