List,

The following example works as expected with MKIV but fails for me with 
LMTX.

    \setuppapersize[A7]
    \setuppagenumbering [location=]

    \definelayer [pageNumber][
                   x=\dimexpr\pagewidth-\cutspace\relax,
                   y=\topspace,
                   width=\pagewidth,
                   height=\pageheight,
                  ]

    \startsetups [setupPage]
         \setlayer[pageNumber]
                 {\hskip\leftmargindistance
                   \inframed[frame=off,leftframe=on,loffset=1em]{\userpage}}
    \stopsetups

    \setupbackgrounds[page]
                      [setups=setupPage,
                       background=pageNumber]
    \starttext
    \page[empty]
    \stoptext

--
Rik