ListGrid: Sorting on a grouped column not working if grouped list is greater than 17

[chrisachillijp]

SmartGwt 4.0

Internet Explorer 8
Firefox 17.0.4

I have a ListGrid which is not DataBound. I push data to the grid using setData method.

Under the following conditions, all true at the same time:
1) Grid is grouped by column A
2) Grid is sorted by column A ascending
3) Grid is sorted by column B descending

I observed that if the list of grouped records is at least 18, the sorting of column B is not right.

This is the sort order that I get (looks like a quick sorting algorithm that is not merging the last step):

A-val 1
B-val10
B-val9
B-val8
B-val7
B-val6
B-val5
B-val4
B-val3
B-val2
B-val1
B-val0
B-val18
B-val17
B-val16
B-val15
B-val14
B-val13
B-val12
B-val11
A-val 2
...