I am working with 4.1.2 and was experiencing the same problem as noted on this stack over flow post :

http://stackoverflow.com/questions/3017706/jqgrid-search-option-hides-the-grid-table

The Searchform was appearing but not modal and hidden underneath the display:block widget.

A quick look for jquery.searchFilter.css in my collection of jquery-jqGrid downloads showed that I has a .css file in