I had a similar problem: I could switch from US to ES keyboard, but not the other way around with Alt+Alt. The reason is that there is no right Alt key in the Spanish keyboard! Now I use the right control key (that I never use) for these tasks... which exists on both layouts.
I had a similar problem: I could switch from US to ES keyboard, but not the other way around with Alt+Alt. The reason is that there is no right Alt key in the Spanish keyboard! Now I use the right control key (that I never use) for these tasks... which exists on both layouts.