Add support for multiple layers. Do not make editing layers the default operation, instead hide it under an "advanced" option for each crosshair. By default, make each crosshair "simple" by supporting a single layer. This will avoid overwhelming the UI with too many options while allowing it for users that seek it.
Adjust rendering to accommodate multiple layers, To prevent overlapping outlines, the current render method paints the stroke for every shape first. Ensure rendering layers supports this method of rendering.
Add support for multiple layers. Do not make editing layers the default operation, instead hide it under an "advanced" option for each crosshair. By default, make each crosshair "simple" by supporting a single layer. This will avoid overwhelming the UI with too many options while allowing it for users that seek it.
Adjust rendering to accommodate multiple layers, To prevent overlapping outlines, the current render method paints the stroke for every shape first. Ensure rendering layers supports this method of rendering.