DDP won the world title at Spring Stampede 1999 in a Fatal Four Way consisting of himself, Hogan, Sting, and Flair after nailing Flair with the Diamond Cutter (Randy Savage made his return after a 4 month hiatus by being the special guest referee for the match and turned on Flair before DDP won the match because of Savage's hatred for Flair).
Shortly afterwards, DDP turned heel by cheating to retain the title when he was defending it against Goldberg on Nitro. The match ended in a no-contest. DDP stayed with his cheating ways until losing the title to Nash at Slamboree.
As for Hogan, IIRC he was started to get cheered so him and Flair did the lame double turn at Uncensored. He took time after Spring Stampede either because of surgery for his knee injuries or probably to film a movie (Shadow Warriors II or Muppets In Space, I can't remember which). He won the title from Savage again on the night of his return and went back to sporting the red and yellow of Hulkamania the following month on Nitro following a backstage segment talk with his son, Nick, who asked him to wear the classic colors again.