Black sketch lines turn blue when adding a 3D sketch line, why?

[cedar.mckay]

I have an all black 2D sketch. I need to add a 3D sketch line. As soon as I add one  3D sketch line the whole sketch turns blue. Why is this happening, and how can I fix this problem?

This question is a side-question of my tricky (to me) boat solar arch project that I'm having trouble with:

https://forums.autodesk.com/t5/fusion-360-design-validate/better-approach-3d-pipe-structure-boat-sol...

[davebYYPCU]

Fully constraining a 3d sketch without the 2d constraints available , will have a huge contribution to your problem.

Was going to suggest keep away from 3d sketches, three 2d sketches so far, but I hit problems in my 3rd sketch.

Might help....