Still I have problem (probably not only me) with invisible box when I turn ragdoll into animation.

When you have not flat terrain then is a problem like on that picture:
https://i.imgur.com/fxWzeaD.jpg
I can't move my ragdoll lower

Using photoshop that box looks like here:
https://i.imgur.com/j1QQWPx.jpg

If I can give you suggestion what you can add to your addon with that "box":

In addon "Animated Prop Tool" Its option where user can change size of that box byself so maybe you can do something simmilar. That will be very great
Picture:
https://i.imgur.com/TPr0YGX.jpg

Still:
"Easy Animation Tool" >" Animated Prop Tool" :D