How to see what messages an object accepts?

[#1]

I know there is a message that shows what messages an object accepts. Can't remember and can't find. Can somebody let me know?

Thanks, 

M.

[#2 · Accepted solution]

The command show properties() will show you.

Names Default To Here( 1 );
dt = open("$SAMPLE_DATA\Big Class.jmp");

show properties(dt);

[#3]

Thanks!