The following is no big problem, and you might already know about it, but I thought that I should report it anyhow.
I use pleco on an ipad. When I read large (novel length) texts in paginated mode, sometimes it happens that in vertical mode (height of pad> width of pad)
the pad doesn't react when I touch the screen anywhere in one complete line of text. I cannot bring up dictionary entries, and if I sweep to the left in this line to change
page, nothing happens. It seems that it is always the seventh line from below that gives troubles. All other lines of text work normally.
If I turn the ipad upside down, so that the text changes orientation, there will still be the same problem on the seventh line from below, even if this line is now
physically in a different part of the pad.
There is an easy cure: Leave paginated move, and then re-enter paginated mode. After than, everything works normally.
I'm on iOS 7.1.2