I've never known where the various conventions come from that guide UI desi gn in apps. There is one feature in PDF viewers that seems to diverge from every other app I use. Double click selects words and double click and dr ag normally selects multiple words. In the various PDF viewers I use it on ly selects a single word and the drag is ignored. I've tried to get this f ixed in Sumatra but so far it has gained little recognition as being a "bug " and there doesn't seem to be a lot of interest in adding it as a feature request.
Seems both Acrobat and Foxit work the same way and are cited as a reason to not change Sumatra. Why would PDF readers diverge from the other apps tha t work this way? Why would anyone think matching other, competing apps is the right way to go rather than matching the many other apps that do relate d tasks on other types of files (like editors and browsers and PDF viewers built into browsers)?
As a result I have to shift my mental gears every time I use a PDF viewer a nd want to select a sentence.