How can I get the caption for the vertical figures (figures 2 and 4 in 
the example) aligned below the figures with the caption width limited to 
the figure width? Sorry for the noise -- I am sure I am missing 
something simple, but I cannot find it at this point. (Running current 
beta and earlier versions, so it does not appear to be a regression.)

      \showframe
      \setuppapersize[A4][A3,landscape]
      \useMPlibrary[dum]
    %% Enable the first set of three for wider picture margins,
    %% and the second set of three for standard picture margins
      \def\FullWidth{\the\dimexpr(\textwidth+2\margindistance)}
      \def\PicWidth{\the\dimexpr((\FullWidth-2em)/3)}
      \def\RPicMaxWidth{\the\dimexpr(\PicWidth-\margindistance)}
    %\def\FullWidth{\textwidth}
    %\def\PicWidth{\the\dimexpr((\FullWidth-2em)/3)}
    %\def\RPicMaxWidth{\the\dimexpr(\PicWidth)}

      \setupcombinations[width=\FullWidth]

      \definefloat [rightFigure][rightFigures]
                   [figure]
      \setupfloat  [rightFigure]
                   [
                    location=right, % this does nothing!
                    maxwidth=\RPicMaxWidth,
                   ]
      \setupcaption[rightFigure]
                   [
                    width=\PicWidth,
                    location=bottom,
                    align=middle,
                   ]

      \definefloat [leftFigure][leftFigures]
                   [figure]
      \setupfloat  [leftFigure]
                   [
                    location=left, % this does nothing!
                    maxwidth=\textwidth,
                   ]
      \setupcaption[leftFigure]
                   [
                    width=\PicWidth,
                    location=bottom,
                    align=middle,
                   ]

      \define\testtext{\dorecurse{5}{This is some text to fill up the
        space. }This is some text to fill up the space.\par}

      \starttext

        \testtext

        \startplacefigure[title={You see this caption!}]
          \startcombination[3*1]
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf a.} Subfigure
           \stopcaption
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf b.} Subfigure
           \stopcaption
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf c.} Subfigure
           \stopcaption
          \stopcombination
         \stopplacefigure

        {\em\testtext}

        \startplacerightFigure[title={Can you see this one?},
            location=right,
          ]
          \startcombination[1*2]
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf a.} Subfigure
           \stopcaption
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf b.} Subfigure
           \stopcaption
          \stopcombination
        \stopplacerightFigure

        \dorecurse{5}{\testtext}

        \page

        \testtext

        \startplacefigure[title={You see this caption!}]
          \startcombination[3*1]
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf a.} Subfigure
           \stopcaption
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf b.} Subfigure
           \stopcaption
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf c.} Subfigure
           \stopcaption
          \stopcombination
         \stopplacefigure

        {\em\testtext}

        \startplaceleftFigure[title={Can you see this one?},
            location=left,
          ]
          \startcombination[1*2]
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf a.} Subfigure
           \stopcaption
            \startcontent
             \externalfigure[dummy][width=\PicWidth]
           \stopcontent
           \startcaption
             {\bf b.} Subfigure
           \stopcaption
          \stopcombination
        \stopplaceleftFigure

        \dorecurse{5}{\testtext}

    \stoptext


-- 
Rik