Curve direction arrows in markups not saved in .mrk.json?

It looks like turning on/off direction arrows in curves is not saved to the .mrk.json file. Is this by design? Seems like it would be useful… I’ve added some code to .slicerrc.py to turn on arrows by default, but is there a reason it’s not saved/restored in the .mrk.json file?

OK, clarification here - direction arrows are saved in the .mrml file.