Add setting for extended-symbols-on-shift

[535]

If there were an option to change the alt keys from the main symbols to the extended symbols, it would be possible to type four sets of characters without changing keyboard "pages". The "e" key, for example:

1. tap — "e"
2. long press — "3"
3. shifted tap — "E"
4. shifted long press — "×" (multiply)

[tmiv44]

+1
or have the Alt key work as a multi-touch, so you hold alt and push the key you want and get the symbol, but the keyboard page never changes.