I am using gnome calendar in Ubuntu 16.04 (Unity or Gnome) to display my Google calendars. This week something happened to the time portion of the event entry window, whereby any time entry forces it to be listed as am and I only have a 12 hour range of numbers it will take (i.e., from 0 am to 12 am). I can't seem to fix this even by changing the date and time settings in Ubuntu to 24 hr. If I enter the event on Google calendars, or even the California calendar app, the entry shows up correctly in gnome calendar. I just can't enter the full range of numbers in gnome calendar itself. I suspect that a preference setting has gone awry, but I can't find any preference setting within the calendar application that would allow me to address the problem. Could there be pref settings for this app in a configuration file somewhere? Incidentally, I did try to reinstall the calendar application, but that didn't help.