I have Ubuntu 13.10 installed. from Text Entry Settings I added Arabic to keyboard layouts then tried to change the 'Switch to next source using: ' field. I tried to set it to Shift+Caps Lock and Alt+Shift and other combinations but no luck, It does not change,just leaves a blank field.
I tried to change the keys from Keyboard Settings > Typing > Switch to next source, same results, whatever combinations I try it leaves the field disabled.
how do I change the keys and fix this problem ?? I never had this problem in any of previous Ubuntu releases.
Hint: I had Ubuntu 13.10 when it was still in Beta and then updated to the last release, This problem existed all along. I don't know if that can be relevant but just in case.