jQuery Grid Plugin - jqGrid

jqGrid 4.1.2

Got this error "Uncaught TypeError:  Cannot call method 'indexOf' of undefined".

Error occurs only in Chrome, I am using version 14.0.835.202

Error occurs in jquery.jqGrid.src.js:2496 in the following line of the setSelection event:

if(!pt || pt.className.indexOf( 'ui-state-disabled' ) > -1 ) { return; }

The className is undefined in the DOM in Chrome, (it worked in IE9 and Firefox 3.6.8).

This prevents any onSelectRow event from executing.

Any ideas?  If not, any way to hack around it (by forcing a pt.className?)

Thanks for this great component - the virtual scrolling feature is excellent.