jQuery Grid Plugin - jqGrid

I'm using the latest versions of jqGrid and jQuery on a page with master/detail grids. 

Inside the main jQuery "ready" loop, I've defined both the master grid and the detail grid.  I've defined a url parameter for the master grid, but not for the detail grid because that url will be constructed based on the row selected by the user in the master grid.

This works fine in the following browsers Firefox (Windows), Chrome (Windows), Safari (iOS) and IE9, but it does not work at all in IE8.  What happens is that the browser (IE8) seems to freeze and all controls on the page become completely unresponsive.  Indeed, the browser can't even be moved or minimized until the freezing stops (which takes about 30 seconds).  I used Fiddler2 to see what was going on and discovered that IE8 makes 2 unexpected connections in addition to the expected AJAX call:  first it reloads the entire page containing the jqGrids, and then it tries to load the .dtd link specified in the DOCTYPE for the page.  It's this attempted access of the .dtd which takes 30 seconds and freezes the browser.

The workaround that I discovered is to specify a "dummy" url parameter for the detail grid.  (I use "http://www.google.com"  The actual url doesn't matter since it will be replaced by the url constructed after the user selects a row in the master grid.)  Once I specify this url, everything works great, even in IE8, and the browser no longer makes the two "extra" connections (reloading the page and trying to connect to the .dtd.)

Is this a bug or expected behavior or am I doing something incorrectly?

Thanks for reviewing.  (I can post my code if necessary, but I thought my explanation might be easier to read.)

--Jeff