When everyone finds out that Shelby has been on dialysis and is going in for a kidney transplant, Shelby has her right arm up on the maicure table. Then they pan around to see everyone's reaction and when they get back to Truvy and Shelby she puts her right arm up on the table and says "So you better get going on my nails."
Maybe just maybe Truvy hadn't finished her right hand yet and Shelby was telling her she'd better start doing her nails again!!! I don't know just a thought.
Since Dolly Parton was so concerned with Julia Roberts' arm, she had no time to finish the manicure that she never actually started on, which was on her right hand. So when she stuck her right arm up on the table..she was telling Dolly Parton to finish her right hand..not start on her other one. Catch my drift?
Did you ever possibly think that maybe Shelby put her arm down? If it had shown that her arm was on the table before and then the camera went to everyone else in the room, then maybe, just maybe she could have put her arm down for something or just happened to move it. Look harder honey. =o)~ You will probably find some other slip-up.
I think Truvy wasn't done with Shelby's right hand. It does take a while for a manicure. By the way, Blue Brit, it's Truvy. And for future reference for everyone, it is not Ms. Weezer, it is Ms. Ouiser in the written play. Remember, it's the south.