http://flavorwire.com/416972/the-frasier-conspiracy-was-tvs-longest-running-character-a-success-out-of-spite-to-shelley-long/

A "Cheers" writer debunks the rumors, which Kelsey Grammer perpetuated in his memoir.
Read more at http://www.hitfix.com/tv-tattle#d0xhfQhRv0BbELJz.99

Sounds bogus to me but interesting. However if she really hated him as the article claims, then why would she even bother guesting on Frasier at all? I know she was in at least two episodes.

I'm glad they kept the Frasier character. He and Lilith are two of my favorite characters.

I'm glad they kept the Frasier character. He and Lilith are two of my favorite characters.
Mine as well. As intellectuals, they provided a good contrast to the hoi polloi in the bar.

I think the writers recognized that, which is why they kept bringing Frazier back to the show. And I think that part in Kelsey Grammer's autobiography about Shelley Long was meant to be self-depreciating humor (although there's always a kernel of truth to these things). The truth is, the writers thought Frazier worked well on the show, and loved Grammer's performances.

(It's also equally clear that no one on that show liked Shelley Long).