Hi, I think it would be a very nice feature for productive, focused, concentrated writing, if LyX has a "focus mode" similar to iA Writer for Mac. That means, that only the sentence you're currently writing (the cursor is in) is normal black. All other text is displayed in grey. That has many advantages:
1. You can better concentrate / focus on the current sentence. That makes concentrating easier and your writing more productive. It helps non-distracting writing. 2. It's much easier to see, if a sentence gets too long. You don't have to search where it begins, but see with one glimpse, if it is too long. And to make it perfect, there should be a shortcut to move uo/down between sentences, that are displayed black while the rest alsways turn grey. I think, such a focus mode would be a great addition for a non-distracting writing-experience. Greetings, Carlos