Just to be clear, what I'm seeing isn't the inability to have BOTH the lead sheet and notation windows open at once: It's that the lead sheet window DOES NOT WORK. If there was a way of first closing the notation window, then opening the lead sheet window, I could live with that. That's not the case. What we have is that the recent updates have BROKEN a feature that has worked fine for years! Please fix it!!
Well, I think I agree with you.
The problem is that you cannot have the Notation Window and the Lead Sheet Window open simultaneously.
If you open the Notation Window, then select the Lead Sheet Window, the Notation Window immediately changes to the Chord Chart Window.
Is that the same problem that you are having?
In your previous version, could you have the "lead sheet and notation windows open at once"? I don't believe that I was ever able to do this.
What was the version that you updated from that previously worked?