I have written about these problems some months(year?) ago, but since I noticed today that the problem persists, I write again. The first problem is with sizes of nested fences, the second one with the size of lucida fences. The test file is pasted below.

Let me also take the opportunity to thank for the nice card that arrived in the mail. Last year's card was still on the refrigerator, and its message is kind of funny/scary in retrospect. I wish you all a good 2021!

/Mikael

\definemathfence[Set][left="007B,right="007D,command=yes]
\definemathfence[Paren][left="0028,right="0029,command=yes]


\starttext

When using nested fences, if one set the size of the outer one, it applies also to the inner one, with the same size:
\startformula
\Paren[size=2]{\int_0^1 \Paren{f_1(x)+f_2(x)}\,dx}
\stopformula
If one is not specifying the size of the outer fence, it seems to work correctly:
\startformula
\Paren{\int_0^1 \Paren{f_1(x)+f_2(x)}\,dx}
\stopformula

\startformula
\Paren{\int_0^1 \Paren[size=1]{f_1(x)+f_2(x)}\,dx}
\stopformula

With most fonts, the sizing works well:

\startformula
\Set[size=0]{a}\quad
\Set[size=1]{a}\quad
\Set[size=2]{a}\quad
\Set[size=3]{a}
\stopformula

\switchtobodyfont[lucidaot]
If we switch to lucida, the \type{size=1} and \type{size=2} are the same:


\startformula
\Set[size=0]{a}\quad
\Set[size=1]{a}\quad
\Set[size=2]{a}\quad
\Set[size=3]{a}
\stopformula


\stoptext