Thanks for your answer.
I stopped using Daslight 4 for some reasons explained briefly above, mainly unexpected issues during shows. It's a personal decision, although I'm sure that D4 has been improved in the meantime.
I've switched to another software and interface. Nevertheless, Daslight 4 is still installed on my PC's and I visit this forum from time to time, trying to help people when it is possible. Really, I spent a lot of good times testing D4 and reporting bugs and suggestions. I do not exclude to do it again in the future, who knows...