The treetable is not compatible with IE9 rows inside the node already opened when open it again it is load another rows.
http://docs.webix.com/samples/15_datatable/30_treetable/02_dyn_loading.html
you can try to open it in IE9 and IE10 stile the same but IE8 it is shows correctly.
I can confirm the issue. Fix will be included in the next build.
If you need the fix ASAP and you have a support subscription - be sure to open new support ticket.