Core decks vs extensive reading

For the text problem, try a different option in the drop down menu of ITH. If none of those work, you might have to search for a hook code that works on that engine. Normally the former will work. I'd show images, but I'm away at the moment.

For the other problems, I don't know. I've never had that scrolling problem, and I've never tried to use it with subtitles (something tells me that any potential fix, assuming one exists, will be far more difficult than just opening the subtitle file in a text editor).