Cannot assign an action to dead keys, keys with accented letter, and some others.

Hi,

I am unable to assign certain keys to an action. For example I can't assign to « Walk forwards »:
- accented letters or otherwise exotic symbols keys like « é », « è », « ê », « à », « ç » or those french quotes I'm using;
- dead keys like « ^ »;
- more surprisingly, certain keys like « $ », « " », « + », « % », « * » or parentheses.

This problem wasn't happening in Minecraft 1.5.2 . The key assigned in such cases already appeared to be « NONE » but it did in fact execute the correct action if you nevertheless tried to use the corresponding key in-game.