Duplicating drawings

Hello,

I’m new to Toon Boom harmony and I’m just familiarising myself with the different functions and so on

The ‘duplicate drawing’ function seems to be broken for me, or not behaving properly.

Sometimes, it’ll let me edit the new image I’ve duplicated fine, and won’t effect the previous drawing, as it should. But most times I’ll;

Copy the previous drawing onto a new frame

Select ‘Duplicate drawing’

Try for example, changing the fill from green to blue, and then both images are still somehow both linked, and the new image is still green? I can see in the Drawing subs window that the original is affected too when I colour the new one in.

Is there a setting I need to change in preferences or?

Appreciate any kind of response!

Thanks

Just another note;

It seems to only be the fill that alters. I can draw a line or a cross or whatever on the duplicated frame fine. But as soon as I modify the fill, it affects the original layer.