I think I discovered why the math symbols \Omega, \otimes, \nleqslant,
and \rightleftharpoons are currently not displayed (bug 3181).
>From the lib/symbols file, it turns out that the codepoint of all
of them is 173=0x00ad, and, according to the following code
// hide soft-hyphens by default
if (uc[i].unicode() == 0x00ad || qIsControlChar(uc[i].unicode()))
glyphs[pos].attributes.dontPrint = true;
in the Qt4 qscriptengine.cpp source file, they are hidden by default.
I don't see an easy solution to this problem, other than changing their
codepoint both in the lib/symbols file and the font files (fontforge can
do this).
--
Enrico
