Hello,

apparently, there are some missing lines in the css file from the latest version of the jqgrid on github. (dev branch).

Here they are:

.ui-searchFilter { display: none; position: absolute; z-index: 770; overflow: visible;}
.ui-searchFilter table {position:relative; margin:0em; width:auto}
.ui-searchFilter table td {margin: 0em; padding: 1px;}
.ui-searchFilter table td input, .ui-searchFilter table td select {margin: 0.1em;}
.ui-searchFilter .ui-state-default { cursor: pointer; }
.ui-searchFilter .divider { height: 1px; }
.ui-searchFilter .divider div { background-color: black; height: 1px; }

Without theses lines, the advanced searching is not working properly.