Sadly, most cross-platform apps have a shortcut that gets triggered with altgr + key. I use US-International (a layout where almost every key has a symbol mapped to an altgr + key combination), and this is very frustrating, especially with accented vowels áéíóú and ñ (pretty common in Spanish).
This is why I always prefer dedicated windows apps over cross-platform apps.
Even dedicated Windows applications get that wrong on occasion, despite the UX guidelines stating that Ctrl+Alt should never be used for shortcuts for this very reason. Alas, people with a vanilla US keyboard layout won't ever notice ...
Most recent thing that bit me in that regard was ReSharper.
This is why I always prefer dedicated windows apps over cross-platform apps.