This is now (Fx 48~), fixed by bug 1203059 only for "reserved" shortcut keys.
If you think that it's not enough to reserve shortcut keys for some functions, please file a bug for each shortcut key.
Our agreement is, we do NOT enable whole shortcut keys on plugins, e.g., Ctrl+C, etc. So, be careful when you judge if a shortcut key should be "reserved".
This is now (Fx 48~), fixed by bug 1203059 only for "reserved" shortcut keys.
If you think that it's not enough to reserve shortcut keys for some functions, please file a bug for each shortcut key.
Our agreement is, we do NOT enable whole shortcut keys on plugins, e.g., Ctrl+C, etc. So, be careful when you judge if a shortcut key should be "reserved".