I'm basically reopening
this thread.
I'm on Calibre 5.10.1 and using Content Server to read books on an iPhone 7. When trying to highlight a sentence, long press on a word will successfully activate the selecting toolkit, but all I can select is just one word. Dragging the selecting handles does not expand the range, and long press on the word will select the progress bar rather than the book content.
Here's a recording clip to the problem described:
https://www.dropbox.com/s/4y2jo95glf...rver.mov?raw=1