[x] Try and understand better the problem. (it just works now, maybe the problem was elsewhere)
[x] Fix the syntax.
The constrained mark element (mark) had to be temporarily disabled because it was causing major documents disruptions (this element was possibly the main problem in the original syntax).
The problem affects the constrained variant only; the unconstrained mark element (mark_double) is still enabled, tested for, and working fine.
Try and understand better the problem.(it just works now, maybe the problem was elsewhere)The constrained mark element (
mark
) had to be temporarily disabled because it was causing major documents disruptions (this element was possibly the main problem in the original syntax).The problem affects the constrained variant only; the unconstrained mark element (
mark_double
) is still enabled, tested for, and working fine.From my annotated comments, it seems that the problem is in the optional "start with attribute" definition, which matches wildly.
References