My keyboard only works in the last-opened window

Question

I just installed Ubuntu 15.04. When I try to switch windows, my keyboard only works in the previous window unless I minimize it.

For example, I open Chrome and the Terminal. I open the Terminal first. When I switch to Chrome and attempt to type in the address bar, I'm apparently still typing in the Terminal window, even though my Chrome window is active. This doesn't fix itself until I minimize the offending window--in this case, the Terminal.

It happens with any applications that accept keyboard input: web browsers, text editors, etc.

How can I fix this?

Answer 1

I found out what was wrong. I needed to change this setting: Tweak Tools > Windows > Window Action Key to Alt. For some reason, this setting was blank and it was causing all my problems.