The Jingle Bells examples showing the chords in brackets are similar to the ChoPro formatting of lyrics and text. If you type the lyrics into the lyrics box, you can manually type the bracketed chords there as well (or use the method with the Karaoke example above). Then you can make the lyrics window as big as you like because the chords you need are there in the brackets so you don't need to see the chord window in BIAB. I have not done this myself, but it sounds like it would work for what you want it to do.
Good luck.