% virtual extensibles kicking in but only next chain present

\setupbodyfont[palatino,12pt]

\starttext

\startformula
    \underbrace{u}_{1}
    \underbrace{uu}_{1}
    \underbrace{uuu}_{1}
    \underbrace{uuuu}_{1}
    \quad
    \overbrace{o}_{1}
    \overbrace{oo}_{1}
    \overbrace{ooo}_{1}
    \overbrace{oooo}_{1}
\stopformula

\stoptext
