[Utah-astronomy] Albireo: a double star?

I found this a few years ago in the 1978 edition of Burnham's (Burnbaum's) Celestial Handbook Vol. II, page 754, third paragraph:   "Albireo is believed to be a physical pair, although no evidence of ortibal motion has been detected since the first observations of F.G.W. Struve in 1832."   Most of us, including myself, have been telling the public for years that the two were gravitationally bound.  Looks like the proof is lacking or is Burnham's is out-of-date?