What’s with the ‘birther’ battle?

Recently the “birther” movement has been given a big push back into the spotlight with their new spokesperson Donald Trump.  But what is up with the birther movement in the first place, hasn’t that issue been laid to rest yet?
For those who don’t know, a birther is a person who does not believe that President Barack Obama was born in the United States.  They demand that Obama produce and make public a copy of his birth certificate.
Obama has produced a certificate of live birth from Hawaii with the official seal, the Republican governor of Hawaii has said it is a non-issue and there is official record of his birth. There are also people who remember the president’s parents and his birth.
Why should the president be forced to produce his actual birth certificate?  No other president in history has had to do this.  Do the birthers have a legitimate argument or are they simply trying to divert the attention from more pressing issues?