Suddenly it was just gone and reverted back to original defaults.
Beware not to close preference dialog with cancel, always OK if keyboard shortcuts tab is active. No, I did not assign and then close with cancel, that I understand.
Just any time later on - you can open preferences and close with cancel with shortcuts tab active - and it reverted to default.
You don't need to bind/unbind anything.
Just Save/export your bindings - and you will never be sorry. Easy to restore. Otherwise X3 has really been good to me. Liked it a lot at first, and liking it even more by the hour....
Darn fine software.