> talazem@fastmail.fm <mailto:talazem@fastmail.fm>
> 1. August 2015 17:37
> Sorry to pester, but this problem is barring me from moving my book 
> project into ConTeXt this weekend.
>
> The use of linenumbers seems to throw off the R2L mechanism. Example 
> of the problem attached.
>

The culprit is the function "boxed.stage_two" in page.lua which output 
each text line in the line numbering
environment in left to right mode. When you have justified lines 
everything is fine but when you have a ragged
line (e.g. the last line in a paragraph) ConTeXt aligns the context with 
the left margin.

\starttext \showframe

\startalignment[righttoleft,flushleft]

     \input ward

     \blank

     \startlinenumbering
     \input ward
     \stoplinenumbering

\stopalignment

\stoptext

Wolfgang