Also, it's better to not you hide and show panels like you do:
right_pan.flags = 0; // hide the old paddle
right_panbig.flags = SHOW | OVERLAY; // show the bigger paddle

Because setting the flags variable to 0 turns ALL flags off. This is bad if you want to keep other flags. Better do it like this:
right_pan.flags &= ~SHOW; // hide the old paddle
right_panbig.flags |= SHOW; // show the bigger paddle

If you do it like this, you have to set the OVERLAY flags only once and you don't have to set it each time again.