I'd like to change change the actions assigned to the Multimedia key's to be global. As far as I can tell there's no way to change the settings of existing shortcuts in foobar2000 0.9 beta 7. Imo it should be possible to alter existing settings without having to delete the entry first.
After changing, the Add button gives me an error telling me the assignment already exists, the Save All button doesn't do the trick either.

Some other small issues:
You have to double-click existing entries in the Assigned shortcuts section to get the shortcut prefs, shouldn't this be just a single click? Imo this would be a bit more logical.
The Type column name in the Assigned shortcuts section isn't completely correct in it's current context. It's more an Action category instead of an Action type I think. This or the current type group names should be changed.

Just doubleclick on entry You want to change

I did, but the changes don't get saved.

I forget to tell: Press remove and then add.

Like I said in the first post, it shouldn't be required to delete the initial entry first and add a new one, it should be possible to alter an existing entry. Why even bother allowing people to change entries if they can't be saved?