I'm experiencing problems when I attempt to strengthen skills, using the latest version of Chrome on Windows 7: in timed and untimed exercises, after checking a question and pressing 'Continue', the next question will not display. Sometimes this occurs after the very first question, and at other times after two or three. I've tried clearing the browser cache and logging back in again, but the problem persists.

(Note: I was able to successfully complete an exercise using IE11, so this problem appears to be specific to Chrome.)