Tool tip Not working in first row of dhtmlx .

Hi ,
the tool tip is not working for the first row of dhtmlx grid even if it is working for rest of rows . There is some navigation issue also with first row . After selecting first row , i pressed down arrow ,bt it is not selecting second row …any idea?

Please, make sure that the id of the first row i not “0”.
Unfortunately it’s not available to use null as an id of a row.