I got the same axe, same problem. Its the design of the guitar that forces it to do that. I did learn that from now on I throw a strap on a guitar before I purchase it to see how it hangs.

I have thought about taking out one of the neck screws and replacing the top of it with a strap lock and bolting it back in....either that or moving the back strap post.

Of course I haven't done either and still play with it standing up and I am happy with it. Doesn't drive me nearly as nuts as trying to sit and play my strat....stupid finish is so silky smooth that it slides off my leg all the time.