\setupoutput[pdftex]
\setupinteraction[state=start]
\setupcolors[state=start]

\starttext

\tracefieldstrue

\switchtobodyfont[96pt]

\def\FS#1{\framed[width=4cm,height=4cm,strut=no]{\red\bf#1}}%

\definesymbol [empty]   []

\definesymbol [one]     [\FS{1}]
\definesymbol [two]     [\FS{2}]
\definesymbol [three]   [\FS{3}]
\definesymbol [four]    [\FS{4}]
\definesymbol [five]    [\FS{5}]


\setupfield[interaction]
  [width=4cm,height=4cm,
%   frame=off,
   framecolor=blue,
   offset=none,% default offset causes different positioning of walk button and fieldstack
   clickin=JS(Walk_Field{sequence})]

\definefield[Walk][check][interaction][empty][empty]


\definefieldstack[sequence]
  [one,two,three,four,five]
  [frame=off,
   offset=none,% default offset causes different positioning of walk button and fieldstack
  ]


\defineproperty[interaction][layer][title=interaction, state=start]


\vbox{\normaloffinterlineskip
\smashedvbox{\fieldstack[sequence]}%
%
\startproperty[interaction]%
\field[Walk]
\stopproperty%
}

\blank[2cm]
\showfields

\stoptext