Talk about awkward: Lindsay Lohan was celebrating the grand opening of West Hollywood club Apple Lounge with Samantha Ronson on August 14 when she ran into two ex-boyfriends - and an ex-girlfriend! "Lindsay chatted with her ex Harry Morton for a few minutes," a witness explains about the first encounter. "Sam wasn't thrilled." Lindsay, 22, was there to support her live-in galpal, who was deejaying the event. But before the night was over, another of Lindsay's exes, Calum Best, showed up, followed by former girlfriend Courtenay Semel. Although Lindsay's rep says, "It wasn't awkward for her to be with all of her exes," a witness says, "That was definitely enough drama for Lindsay. She made sure the rest of the night was very mellow, drinking little as she smoked and stuck by Sam's side." "Lindsay reassured Sam," a witness says, "by gently rubbing her lower back whenever they were alone." Courtenay Semel dated Lindsay in late 2007, says an insider. Lindsay dated Calum Best for three months in 2007. Harry Morton romanced Lindsay in 2006.