Slow Grouping of Rows
 

My client has a workbook that includes one worksheet with 148 rows and 60
columns. There are four levels of grouping for the columns and three for the
rows. That's probably something that the client insists on. Moving from
level 4 to level 1 for the columns is instantaneous. Moving from level 3 to
level 2 or from level 2 to level 3 takes perhaps three seconds. Moving from
level 3 or level 2 to level 1 takes approximately 45 seconds. The
calculation reaches 100% in about two seconds, so I don't think that it's a
calculation problem. What else should I be looking at?