tooltip on hover on treegrid row not showing

I have added title=“description” in my xml row but on hover I do not see the tooltip.
What could I be missing?
( I have not disabled tooltips)

row have no title attribute. you need to apply this attribute to each cell of a needed row.
Also have a look at the common XML structure here http://www.dhtmlx.com/docs/products/docsExplorer/doc/dhtmlxxml/index.html