I suspect it is the hidden of Sinatra
Because the other pedigree shows it is either hiding the Siamese choc or what the choc is hiding and this is Burmese Platinum or "better = more recessive".
Since Rosa gave her shown fur the Aby Black Silver from that line is definately not hiding.
I don't know for sure it was Sinatra but I consider that a safe bet :-)
P.S. I know for sure it is the hidden of Sinatra on second view because the Siamese Choc is recessive to the Red & White and also Recessive to Russian White so Mom is hiding the Siam Choc or Burmese or what the Burmese is hiding.
Should it be so the Pink & White is recessive to the Red & White it is also a possibility the Pink & White is hiding.
