Until someone comes back to give you a definitive answer, try selecting “activate sketch” first, followed by clicking on the desired plane. If that fails, you may have a corrupted installation which will require attention from Mintronics – assuming that you are in the UK. Drop them an email to support on Monday if the problem persists.
John
Edit. I failed to refresh the page before replying, so didn’t see your reply. Hence it appears that I am ignoring your response. Glad you got it sorted.