Comment 1 for bug 1598999

I also experienced this issue. It happened after I upgraded from Mint 17.3 to Mint 18. Once I set the Input method to None in System Settings/Input Method and then re-login, the panel started responding to clicks. Changed back the Input method to IBus, and the panel stopped responding to clicks. No Input Method had been added in IBus Preferences yet. The act of enabling IBus seemed to trigger the problem.