Yellow side of an angle gets drawn as thin black line

[MarcinCiura]

See Proposition I.V: in \drawAngle{DCE,DCB} = \drawAngle{EBD,CBE}, the sides CE and BD are drawn as thin black lines while they are yellow lines on the picture. This is probably intended behavior but I found no documentation of this feature.

[jemmybutton]

It is intended, but maybe not the optimal one. By default, if an angle is depicted as an arc, its symbol is completed with thin black lines as its sides (Byrne does this in I.V, III.XVI, III.XXII and in other places). It is possible to explicitly state what lines you want to include in an angle symbol (see https://github.com/jemmybutton/byrne-euclid/blob/master/byrne_ru_context.tex#L2019 for example). It's not very difficult to do this automatically, though. So, if you need it, i can add this feature.
Documentation is really poor, i'll try to update it some time soon.

[jemmybutton]

Now you can use \drawAngleWithSides (e. g. c716c04#diff-5a8eec69ed8a2717ec1a6d8ee3f6ac94R2030 ) to get auto angle sides of appropriate colors instead of thin black ones. Keep in mind, that, although it can be used for all the angles, it's most likely much slower.

[MarcinCiura]

Thank you, \drawAngleWithSides is exactly what I was looking for.