Disabling auto-forms/shapes possible?

[deep470]

When I use the whiteboard to train japanese hiragana characters, I can't paint slow. When I stay on the left mouse button for too long, my painted character is transformed into a shape, e.g. a square or a circle. I already disabled all shapes and I am under the impression that the normal pencil shouldn't do autoforms, as there is a separate tool "intelligent drawing".

How/where do I disable this behaviour or is there a better tool to draw letters?