I replicated your AltGr tests. Italian keyboard under Windows support these combos: AltGr+"5": "€" AltGr+"E": "€" AltGr+"ò": "@" AltGr+"à": "#" AltGr+"è": "[" AltGr+"+": "]" Shift+AltGr+"è": "{" Shift+AltGr+"+": "}" With the exception of the first two combos (both producing "€") all the other combos provide the expected character. A little quirk: in the monitor window accented letters are recognized, but not having a glyph the monitor prints the unknown one. The "€" character, on the contrary, is...
I just forgot to add that I haven't tested the bug under Linux or other ports so I don't know if they're affected or not.
Tilde key not accessible in monitor window (italian keyboard)