Example:
------
\definetextbackground[undeftext][location=text,alternative=1,dash=3,background=,frame=off,voffset=-.5ex]
\starttext
Hello \starttextbackground[undeftext]
world!
\page
bbb.
\page
ccc.
\stoptextbackground
\stoptext
------
Proposed patch:
------
--- tex/texmf-context/tex/context/base/mkxl/anch-pgr.lmt.bak 2021-05-07
12:19:30.951643997 -0500
+++ tex/texmf-context/tex/context/base/mkxl/anch-pgr.lmt 2021-05-07
12:19:44.716693548 -0500
@@ -123,6 +123,9 @@
local ht = specification.ht
local dp = specification.dp
-- this is not yet r2l ready
+-- myfix
+realpage=texgetcount("realpageno")
+-- end
local w = d.shapes[realpage]
local x, y = getpos()
if trace_ranges then
------
The module-local variable `realpage` is never changed, which is apparently
a bug.
Best,
GOU Lingfeng