[Ridcully]

In most PDFs when you try to select a word or a sentence the cursor automatically selects everything from there up to the beginning or down to the bottom of the page. It's impossible to select just one word or a few lines. In other PDFs selection works fine just like in reflowable formats.

Does anyone know what causes it or how to convert PDFs so that text can be selected normally? I've had this problem on an older Kindle Touch and now also on the (current?) Paperwhite, and it's a regular annoyance.