I am using a Lumia 640XL running Window 10, version 1607, OS build 10.0.14356.1000.
I've got a problem with the keyboard. I can only type within Microsoft apps (such as Messaging, Edge etc.) but I am not able to type anything on other non-Microsoft apps (such as Facebook, Messenger, 6tag etc.) even though the keyboard does appear when I touch the field. Nothing appears when I touch the letters, numbers on keyboard.
A soft reset didn't work. So how can I fix it?
UPDATE: It's is a problem with the Vietnamese keyboard. i.e. I can type English normally. I have updated the title to reflect the same.