I might have been having the same problem that the original poster was having. I found that the solution for me was that the blue bounding box(which lets me know the text is selected and ready to edit) mysteriously moves off frame sometimes making it appear that the text I would like to edit isn’t being highlighted at all. Additional to this problem, when I do click and drag the bounding box it moves at a different speed than the text it is representing… almost like the text itself is locationally represented by a different frame size? Anyway, it seems like a bug to me so I thought I’d say something.
Regards,
Aaron