Why is the compose key (AltGr) disabled by default?
Solution 1:
- The compose key is the key you define for the purpose and not necessarily AltGr (Right Alt).
- Many keyboard layouts use AltGr by default as a modifier to access 3rd and 4th level symbols included in the layout, and in those cases it's not suitable to define AltGr as a compose key.
I assume it's not enabled by default because there is no obvious key which would be suitable in all use cases. The key you define as a compose key stops working in its original way.