Problem with wrapping jqGrid column headers on IE
Try to use additionally
.ui-th-div-ie {
white-space:normal !important;
height:auto !important;
}
UPDATED: It seems to me, that instead of all this styles it would be better to use one following:
th.ui-th-column div{
white-space:normal !important;
height:auto !important;
padding:2px;
}
It seems work very good in all browsers. See an example here.
UPDATED 2: More information and more demos about the problem you can find in the answer.