texmath-0.6.7: tests/writers/munder8.tex
\underset{\dddot{} }{{x}} \neq \underset{\dddot{} }{{x}} =\underset{\dddot{} }{{x}} =\underset{\dddot{} }{{x}}\underset{\dddot{} }{{x}} \neq \underset{\dddot{} }{{x}} =\underset{\dddot{} }{{x}} =\underset{\dddot{} }{{x}}