How to remove segments of objects from carbide create library items

I’ve been trying to edit out part of a heart outline from a carbide create library image.
i can’t remove any part of the outline that isn’t within the size of my stock.

Is the geometry in question magenta or black? (when not selected)

For the latter see:

and also see:

The tools to use are Node Editing and Trim Vectors and Boolean operations — if you’re still stuck, post the file you are working on here or e-mail it to and we will do our best to assist.