For users like me with not so fast connection, expanding a node while another is still loading messes up the tree. Is there a way to disable the grid while it's still loading? I'm using the latest version (4.1.1)
To replicate, go to http://trirand.com/blog/jqgrid/jqgrid.html -> New in version 3.4 -> Tree Grid Adjacency model and click the expand buttons one after the other in a fast succession.
Try to use loadui:'block' jqGrid option.