Logos Bible Software 4.3 (4.30.0.1516) (Beta).
I have two windows open, one on each of two monitors. I highlight text in second window, go back to first (main) window and select some highlight feature (e.g. yellow background, or "erase") and nothing happens - repeatedly.
I have assigned letters as shortcut keys and they do work.
I'm finding that the highlight pane must be in the same window as the pane that I'm trying to highlight or erase. This did not used to work this way, and I prefer to have the highlight pane open all the time in one place.