toonboom 20 premium not allowing me to add deformers

I’m working on creating a character rig and wanted to add a curve deformer to the arm all the parts are on separate drawings (e.g. eye, pupil, mouth, neck etc) I drew it using the pencil tool and have the colour and line art separated onto their respective art layers but whenever i try to add any deformer I click the drawing I want to apply it to and click on the rigging tool as soon as the cursor enters the camera area every element highlights yellow or red and the cursor turns into a red circle with a strike through it and wont allow me to add any deformer points

any help on where I may have gone wrong would be greatly appreciated