ConTeXt: Four-column footnotes within two-column page layout

I have made a document test in ConTeXt. A two-column layout with four-column footnotes. I need to place the footnotes of each page at the bottom of text area, within a frame.

My ConTeXt script places all footnotes on the last page.

First page:

Second page:

Code

\startenvironment enviro-mmi
\definepapersize[mmi][width=6.5in,height=9in]
\setuppapersize[mmi][letter]
\setuplayout
[
backspace=0.875in,
topspace=0.5in,
footer=0in,
width=5.125in,
height=7.5in,
margin=0in,
marking=on,
location=middle,
]
\dontcomplain
%~ \showgrid
\showframe

\setupbodyfontenvironment[default][em=italic]
\usemodule[simplefonts][size=9.5pt]
\setmainfont[utopia]
\setsansfont[Roboto Condensed]
\setupindenting[yes,next,0.1875in]

\definemixedcolumns[col2]
[
n=2,
grid=yes,
align={width,verytolerant},
separator=rule,
rulecolor=middlegray,
rulethickness=1pt,
balance=yes,
]

\definemixedcolumns[col_notes]
[
n=4,
align={flushleft},
%~ separator=rule,
%~ rulecolor=middlegray,
%~ rulethickness=0.5pt,
balance=yes,
grid=no,
distance=0pt,
]

\setupnotation[footnote]
[
style=\ss,
align={flushleft},
width=fit,
numbercommand=\ss\bf,
margin=13pt,
]
\setupnote[footnote][location=text]
\startsetups flushnotes
\framed
[
frame=on,
offset=6pt,
rulethickness=1pt,
framecolor=middlegray,
width=max,
]
{\startmixedcolumns[col_notes] \placenotes[footnote] \stopmixedcolumns}
\stopsetups

\starttext{}
\widowpenalty=10000
\clubpenalty=10000
\startmixedcolumns[col2]
\input Knuth\footnote{FreeBSD tire ses origines de l'UNIX de Berkeley.}
\input ward\footnote{This does not seem to be implemented yet.}
\input hawking\footnote{Left, right (raggedleft, raggedright).}
\input Knuth\footnote{Distance between columns.}
\input ward\footnote{Draw a line between the columns. Default is off.}
\input Knuth\footnote{FreeBSD tire ses origines de l'UNIX de Berkeley.}
\input ward\footnote{Draw a line between the columns. Default is off.}
\input hawking\footnote{Left, right (raggedleft, raggedright).}
\input Knuth\footnote{Distance between columns.}
\input ward\footnote{Draw a line between the columns. Default is off.}
\input ward\footnote{Draw a line between the columns. Default is off.}
\stopmixedcolumns

\setups{flushnotes}
\stoptext
\stopenvironment

• You should be able to select multiple footnote columns using \setupfootnotes[n=4], but that appears to be a bug. Why don't you post your question to the context mailing lsit – Aditya Sep 15 '16 at 23:45
• Are there any news here? – TeXnician Aug 8 '18 at 17:25
• Last I checked, this was still broken. You have to ask on the mailing list. – Henri Menke Apr 7 '19 at 0:42