Refine seeds of heart

Operating system: window 10
Slicer version:Expected behavior :I want refine seeds

Actual behavior: I want to segment the heart as the tutorial and when I get to the stage of editing the mask (refine seeds) it doesn’t let me use anything from the segment editor, it doesn’t paint, it doesn’t cut, etc. Does somebody knows why it could be?

We need more details to be able to help. Can you provide step-by-step instructions and a few screenshots or share a screen recording of what you do?