That's probably way too vague to be helpful unless someone else knows what I'm talking about, but if nobody does, I suppose knowing that could help motivate me to isolate and reproduce the issue next time it happens.
It's amazing how such a small change makes it so much more difficult to use the Firefox dev tools compared to Chrome. Sometimes I just want to toggle between CSS values and see what is changing, or undo a few changes I made.
And yeah for some reason Ctrl+Left/Right to jump around words, Ctrl+Shift+Left/Right to select words, and Ctrl+Backspace to delete a word, are disabled in the console prompt as well (they do seem to work in all the other DevTools input fields I can see). These are pretty ingrained in my muscle memory so I constantly bump into them.
Also I'm on Linux, in case that matters.
1. JSFiddle. Run a fiddle with a loop (setTimeout/setInterval/requestAnimationFrame). Try to find it in the debugger. Fail
2. Add a `debugger` statement in the loop. Watch as Firefox doesn't display the code in the debugger
3. Add a syntax error, see message in console, click link to code, firefox doesn't display code.