1. try using the "ilists off" button to turn off the ilists and see if you still have the one line missing problem.
2. & 3. rr should not slow down in navi unless the pc you are using is very old. destiplus is using a different window name from "destinator" that's why it diesn't embed properly the first time, this will happen no matter what skin you use. search the RR forum for links to embed destiplus.
4. I will look at adding a slider on audio screen in the next release ...