As I like a minimalist approach I've reposition my quest window screen so the bottom right of its window is against the bottom right of my screen.

Now let's say I star the game with 1 open quest. It will be position at the bottom of the quest window, which with my hud layout is at the very bottom right of the screen. Now I acquire a few more quests. Rather than the 1st quest being pushed up the screen so the others can fit, it just remains stuck in place leaving the new quests off screen.

To correct this I have to go back into my HUD layout, move the quest window up a little and save it, check that the quests are properly in place, then go back into HUD layout and move the window back to the bottom right where I prefer it.

Seems like there's a hidden scroll bar function of some sort that doesn't kick in if the text goes off screen.