Each sentence or paragraph is another hurdle to clear. Marking a selection provides the satisfaction of marking that I cleared it (and allows me to avoid reread

Each sentence or paragraph is another hurdle to clear. Marking a selection provides the satisfaction of marking that I cleared it (and allows me to avoid rereading too much when resuming after an interruption or break). I get extra annoyed when something prevents this. For example, a PDF viewer that loses a selection on a shift-click, rather than expanding it. I feel this actually increases the effort of reading, by taking away the easy tracking benefit.