It sounds silly, but it worked for me...
When I was using PoserPro (the first one that's more like P7) and I wanted to delete something, I'd press the delete key and, yes, it would seem to take for ever for anything to happen. What I discovered (on my system, can't say it will be the same for others) was that if, during that interminable wait, I moved the pointer over to the library palette, PPro would spring back to life the second I did this.
It was so strange and quirky, and it became my natural reaction to move the pointer to the library palette after every delete, that I didn't think to ask if this happened for other people. (The Delete Delay doesn't happen now I'm using PPro2010, but for a few weeks after first installing it, my reaction to deleting an item would be to search for the library palette and want to move my pointer in that direction!)