I deleted the 4 default kb shorts in Increase & Decrease Font size and added my own (Ctrl+↑ and Ctrl+↓), when I exited Preferences I got this error:
Error: Unhandled error
Uncaught TypeError: Cannot read property 'range' of null
Error at userscript:viewer.js:13566:23
Traceback (most recent call last):
at Number.onload (userscript:viewer.js:12007:21)
at IframeBoss.content_loaded (userscript:viewer.js:17362:18)
at IframeBoss.content_loaded_stage2 (userscript:viewer.js:17397:18)
at IframeBoss.onscroll (userscript:viewer.js:17477:22)
at IframeBoss.update_cfi (userscript:viewer.js:17452:19)
at at_current (userscript:viewer.js:13644:27)
at x_loop (userscript:viewer.js:13625:31)
at at_point (userscript:viewer.js:13566:23)
TypeError: Cannot read property 'range' of null
After dismissing that I got a spinning wheel and message about reloading an index......html file (sorry my Autocopy 'missed' it) - I quit the viewer. When I restarted the viewer my kb shorts were working
Usability - on exiting the 'dialogue' for changing a kb short I was back at the top of the list (i.e at Navigation Back) -- I find that irritating. IIRC the v3 server might be similar, but I'm still using version 2 server.
BR