The issue happens on web (and on web based UIs such as Electron apps) outside of text input fields or textareas.
This is how to reproduce:
1. first we doble click on the first word of the line, to create a selection
2. At this point we expect that Cmd-shift-rightarrow will expand the selection to the rest of the line. But it doesn't because this key combination only works inside a text input or textarea. In every other desktop OS I can do shift-End at this point, and select the rest of the line.
3. option-shift arrow does work, but selects one word at a time so it is cumbersome to use
4. I had been told that I could use fn-shift-arrow in this case, but that selects all text until the end of the page (that's the one I was thinking about in my previous comment)
I just tried and reproduced the issue in Chrome and Safari.
