In the "preferences" menu there is a mention of
"proportional fixed font" which I assume should be
"fixed font"
If you type, for example, describe("gcd") there are several items
listed and you are invited to type one or more of their
numbers.
It seems you must terminate the line with a ";" or
nothing happens. But the ";" is left over and becomes
a null command line after the describe() is finished.
RJF