Marley is not allowed to chase cats. I do not allow her to chase cats while we are on walks or visiting a cat friendly home. If I catch her harassing or chasing Bob, I'll send her to her crate for a time-out.
I have to change my strategy for 2011. I've been home sick and I've managed to observe Bob and Marley during the day. I've discovered a horrible fact, while I've worked on Marley's behavior, I've totally neglected to curtail Bob's behavior.
Most of their interactions begin by Bob walking to Marley's bed. He'll sniff her bed, freeze and then flick his tail. Marley waits until Bob flicks his tail and then the chase is on! They run around the apartment until Bob decides to stop. Marley politely stops about a foot away from Bob and walks away.
At times, Bob will stop about a foot away from Marley and do a modified play bow. As soon as Marley looks at him, he flicks his tail and they are off for a quick game of chase.
At this point, I'm at a loss as to how to teach Marley not to chase all cats.