On 2016-12-29 11:31, MF wrote:
Hello list,
please take a look at this:

\setupbackgrounds[text][frame=on]

\starttext

Preceding text.

\startplacetable[location={none,fit,force,here,middle}]
\bTABLE
  \bTR
     \bTD $a_{11}$ \eTD \bTD $a_{12}$ \eTD
  \eTR
  \bTR
     \bTD $a_{21}$ \eTD \bTD $a_{22}$ \eTD
  \eTR
\eTABLE
\stopplacetable

Following text.

\page

Preceding text.

\startplacetable[location={none,fit,force,here,left}]
\bTABLE
  \bTR
     \bTD $a_{11}$ \eTD \bTD $a_{12}$ \eTD
  \eTR
  \bTR
     \bTD $a_{21}$ \eTD \bTD $a_{22}$ \eTD
  \eTR
\eTABLE
\stopplacetable

Following text.

\page

Preceding text.

\startplacetable[location={none,fit,force,here,right}]
\bTABLE
  \bTR
     \bTD $a_{11}$ \eTD \bTD $a_{12}$ \eTD
  \eTR
  \bTR
     \bTD $a_{21}$ \eTD \bTD $a_{22}$ \eTD
  \eTR
\eTABLE
\stopplacetable

Following text.

\stoptext

It's the same table repeated on three pages, with some preceding text
and some following text.
Only the "location" option of \startplacetable is modified across
pages: "middle" in page 1, "left" in page 2, "right" in page 3.

When I use location=middle (page 1), the table is centered and the
"Following text" goes after (under) the table. This is what I want to
achieve: the following text should be under the table.

Using location=left or location=right, the "Following text" is not
placed under the table. How can I achieve that?

Thanks in advance,
Massi
Consider your third example, slightly modified:
\startplacetable[location={none,fit,force,here,right}]
\bTABLE
  \bTR
     \bTD $a_{11}$ \eTD \bTD $a_{12}$ \eTD
  \eTR
  \bTR
     \bTD $a_{21}$ \eTD \bTD $a_{22}$ \eTD
  \eTR
\eTABLE
\stopplacetable

Following text.

Following text.

Following text.

Following text.
And this example, with a frame around the table:
\startframed[frame=off,align=right]
\startplacetable[location={none,fit,force,here}]
\bTABLE
  \bTR
     \bTD $a_{11}$ \eTD \bTD $a_{12}$ \eTD
  \eTR
  \bTR
     \bTD $a_{21}$ \eTD \bTD $a_{22}$ \eTD
  \eTR
\eTABLE
\stopplacetable
\stopframed

Following text.

Following text.

Following text.

Following text.

The float location left (right) allows flowing text around the float. You do not want that, so do not use it.

--
Rik Kabel

Thank you Rik,
you solved my problem.
I've realized that \startplacetable is not necessary:

\starttext

\startframed[frame=off,
             align=flushleft, % table aligned to the left
             width=broad,     % the frame takes all the text width
             offset=overlay,  % no space around the table
             ]

\bTABLE
  \bTR
     \bTD $a_{11}$ \eTD \bTD $a_{12}$ \eTD
  \eTR
  \bTR
     \bTD $a_{21}$ \eTD \bTD $a_{22}$ \eTD
  \eTR
\eTABLE
\stopframed

Following text.

Following text.

Following text.

Following text.

\stoptext

Best greetings,
Massi