Can you confirm that if you increase the height of the composer to be above the height of the keyboard then it works?
It seems like a bug in android/galaxy tab where if the keyboard goes fully over the composer it will blur elements, and given that if you blur the input there’s no need for a keyboard, then the keyboard is hidden.
I don’t have any idea to fix it at the moment, all I can tell you is the workaround to slightly increase the composer height.