I'm having the same problem as OP, and I don't understand your answer. I've recently upgraded to biab 2024, and no matter whether I am in notation or chord sheet mode, hitting lead sheet (or selecting it from the window menu) takes me or keeps me to chord sheet. I've had older versions of biab for years (like mid-teens versions), and this has always worked fine. Stopped working with the update. You seem to be saying there are too many windows open, but I see no way of closing them and then choosing lead sheet window. Only way I can now see the entire song sheet is to print it to pdf, which of course lacks all interactive features.