With Startup Code Editor opened, save and close the parent worksheet. Any unsaved changes in the Code Editor are lost.

The documentation says that Subgroup(c) returns the subgroup of the coset c.

Also, the display of Elements(lc) is garbled in Maple as well, not just in the image.

evalf(int(GAMMA(s), s = 1-I*infinity .. 1+I*infinity)); # careful

There seems to be no way to terminate this computation. After clicking "Interrupt the current evaluation", the worksheet is still unresponsive, I cannot edit or copy the contents.

I can close the document, but even after I quit Maple, mserver.exe is still running and I have to terminate it manually.

This is in Maple 2017.2, system="X86 64 WINDOWS", wordsize=64.

int(1/(s^2+1), s = 1-I*infinity .. 1+I*infinity); # as expected
                               0

evalf(Int(1/(s^2+1), s = 1-I*infinity .. 1+I*infinity)); # Pi?
                          3.141592654

So evalf(Int(...)) either doesn't know how to handle complex infinite endpoints or handles them in a way incompatible with how int() does it.

convert(arctan(y, x), abs);
                             / y + I x \
                        -I ln|---------|
                             \|y + I x|/

The output has x and y swapped. Further, for complex x and y it's wrong even if x and y are swapped back, because Maple's definition of arctan has sqrt(x^2+y^2) in the denominator, which isn't the same as abs(x+I*y).