Now it all makes sense.
Thanks Andrew. This answered a question that's being bugging me for over a year now.
I've been a pen centric Windows PC tablet user since Vista. The digital ink/stlus conventions have remained consistent over over that ten year plus period. Windows 10 1709, foistered upon an unsuspecting pen community, completely broke those conventions overnight. Cue stylus users immediate outrage. And what did we get in return for trashing our workflow? A digital on-scren ruler.
If Microsoft want proof their imbelicity hasn't gone unnoticed than I suggest they ask why HP's state of the art zBook x2 Tablet PCis ships with Windows 10 1703, with Windows Update tuned off as default behaviour.