Novell GroupWise 2012
Since the upgrade to GroupWise 2012, getting the calendar to load in WebAccess takes anywhere from 50 seconds to almost 2 minutes. All browsers behave the same way. This particular user was loading a multi user calendar with quite a few calendars to open.
It turns out that this particular user also had almost 1500 old tasks that had never been marked complete and year after year they continued to roll forward. Once they were all marked complete, the calendar opened right up.