Wrong classnames generated in Version v36 130619 TreeGrid

I’m using the Professional dhtmlxSuite_v36_130619
and I have the Problem that the grid will not rendering correct.
There are some rows with:

and some other with “nsc”, “region”, …

.... On initial the user defined class will be double without space.

after a mouse click in any cell it will look like the same in firebug but:

After “cellselection” it will be correct, the class looks fine. I only wonder about “null”.
But this was in earlier version, too.
Please can you bugfix the current version?

Thanks!

Please, open ticket at support.dhtmlx.com so we can provide you the fixed dhtmlxgrid.js