When the row had a lot of child rows, whenever I tried to expand or collapse it, it was taking about 3-4 seconds to do it (unnaceptable ).

The solution I found was to modify the grid.treegrid.js and remove the "context" information from the selector.

expandRow: function(record) {

....

//$("#" + id, $t.grid.bDiv).css("display", ""); //ORIGINAL CODE (SLOW)

$("#" + id).css("display", ""); //NEW CODE (FAST)

...

},

collapseRow: function(record) {

...

//$("#" + id, $t.grid.bDiv).css("display", "none"); //ORIGINAL CODE (SLOW)

$("#" + id).css("display", "none"); //NEW CODE (FAST)

...

}

We all know that using context was supposed to speed up the selector, but in this case it was doing exactly the opposite...

After removing the context, the expand/collapse operation now takes ~1 second... good enough.

I'm not sure this was the more appropriate way to achieve it, but it worked for me. 

Hope it helps.