I have a stair that along one side of the sloping part is a window.
I have 2 railings along this stair, 1 is a chair rail, the other is a wainscot panel.
Obviously the chair rail and wainscot cannot be built to cover the window.
How can the railings be "cut" around the window?
I know how to start/stop the chair rail, but the wainscot needs to continue under the window (keeping in mind that the window is horizontal and the wainscot is sloping with the stair.)
You might consider using a separate "finish wall" with and edited profile instead of a railing for this application.
The wall "base" could be part of the stair--as a custom stringer profile.
Well, that is true--I suppose I'm suggesting that all of the wainscoats could be walls, not railings.
Then schedule them all as walls.
The sweep at the top of the wainscoat where it is angled up the stair could be a bit of a problem--
it could be modeled as an in-place family, a line-based family, etc.
I'm not sure how to edit the railing at the window as you are trying to do. I do undrestand the efficiency and automatic nature of using railings to follow the stairs--makes a lot of sense.