@leocg Ah, Chrome password generator works on another page. I guess it didn't detect it was a password field on the last page I tried.
But they are not the same. Opera always uses lower and upper case letters only. Chrome randomly uses a mixture of numbers, symbols, lower case, upper case. Although sometimes there is no number and the site won't accept it, it's better.
So Opera is not using it, or not using it the same way.