Most of this discussion involves events at the end of Harry Potter and the Deathly Hallows so if you haven't read that book and don't want spoilers, then stop reading right now.
It's not clear whether limbo is something everyone moves through in Harry Potter when they die, but when Harry is killed, he not only ends up there, but Dumbledore is there, waiting for him.
Did Dumbledore wait for him all that time, in limbo, until Harry showed up? Did he have any way of watching what Harry was doing in that time? Or did he have a way to enter limbo when Harry did to meet him there?
And once Harry was gone, was Dumbledore able to move on, or would he be stuck there?