Window 7 64 bit Thunderbird 31 and Lightning 3.3. I recently upgraded Thunderbird 31. When I open the calendar and try to click on a day the calendar starts randomly changing months. It will do this even if my mouse moves over the face of the calendar. It is impossible to enter any data as the months will change any time. I have tried to wait until it settles down but at any time it will start changing months. therefore the calendar is useless.

I have used all versions of Thunderbird and Lighting and this the first time I have had a problem with Lightning. My mouse is a Logitech Performance MX. I have uninstalling and reinstalling Lightning but to no avail.