jQuery Grid Plugin - jqGrid

Hello, my grid doesn't work when I am attempting to sort the column on grouped data, it produces duplicate groups. I am using jgGrid 4.5.2 and jQuery 1.10.2. We have upgraded jQuery from 1.7.1 to 1.10.2 and jqGrid to 4.5.2 from 4.4.0

Below is the code from the group change method:

grid.jqGrid('setGridParam', { grouping: true, groupingView: {groupField: [groupByText],

formatDisplayField: [ function (displayValue) {  {

return String(displayValue).toLowerCase(); }],

isInTheSameGroup: [ function (x, y) {return String(x).toLowerCase() === String(y).toLowerCase(); } ] } })

It created the Groupings based on the value selected from the drop down (dynamicaly changing the group) but after that when I tried to sort on grouped data, it created the multiple groups, the listings on the grid actually sorted by the sort field though.

Can some one please help me resove the issue?