There is no field where you can
a) copy current ticket subject at all and
b) if subject is a bit longer, there is no place, where you can see the subject.
Yes you can see it from the original post, but not if you have changed it after that.
And yes it is shown in the list BUT you can not copy it as a text and if text is longer, you can not see the whole text AND you can not make the column wider.