Hi Pilou - yes that is normal for the first point, the first point of a circle can be snapped on to any snap point as per normal.

But if you have picked a first snap point that aligns the circle to a surface normal plane, then the second point will ignore snaps that are not on that same plane (while picking in the 3D view).

Otherwise if it did not do that, there are 2 other choices -

#1 - allow any other snaps. This has a bad consequence of basically eliminating the ability to sketch a circle normal to a surface because you'll get a whole bunch of snap points such as "on srf" ones that would be off of that surface normal plane.

#2 - allow any other snaps but project them on to that surface normal plane. this allows for drawing the circle aligned normal to a surface, but tends to cause major jumps in the size of the circle as snaps on the back side of the model are targeted and projected to the plane.

I could possibly incorporate some setting to avoid the suppression, but it would help if I could see what is the desired final circle in this particular case.

- Michael