jQuery Grid Plugin - jqGrid

I'm using jqGrid version 4.5.2 with searchOnEnter set to true when I call navGrid to add the search button to the pager. When I click the search button, the single search dialog appears as it should. Then, I perform the following actions to reproduce the bug:

1) Change the search field using the drop-down control

2) Press tab or click on the the text box, then type the string to search for

3) Press the Enter key

When I press the Enter key, it doesn't detect that I have entered any text in the search box. If I have searchrules:{required:true} set up for the selected field, I get a red warning that the field is required. If I don't have the required field rule set up, then it ignores the text and performs the search with an empty string. If I use the "Find" button rather than the Enter key, or if I don't click on the search field dropdown, the search always works fine.