As the title says.
Roundcube inserts two - above the signature, that's fine I guess, however Gmail (And Google mail for Business) sees this as separator between earlier messages, so hides the signature....
Now I could mail Google about this, but maybe this forum is easier to get a solution
....
I looked a bit through the code, but the --[SPACE] is used to do some trickery when replying and such, so I don't know really what to change for this...
A little test shows that three dashes --- would work.....