HP Intelligent Management Center Standard Software Platform - Manual (Page 502)

In this case, the OLAP grid respects the parent/child relationships between
grid members and sorts the data values accordingly. (Frozen Goods precedes
Bakery, but Pastry follows Frozen Goods.)
In the next example, the Budget column remains sorted in ascending order;
in this case, however, the Break Hierarchies option is selected.
Now the Report Designer disregards parent/child relationships between grid
members and sorts on the basis of data value alone. (Frozen Goods still
precedes Bakery, but Pastry precedes all others.)
You can add up to three sorts to grid rows and up to three sorts to grid
columns. In each case, the first sort takes precedence, and each subsidiary
sort serves to further differentiate between grid data. If you add a fourth sort
to a row or to a column, your first three are removed from the grid, and the
new sort becomes the single, primary sort.
502 Crystal Reports 2008 SP3 User's Guide
Creating and Updating OLAP Reports 19
Sorting and filtering OLAP grid data