is it possible to overridden or extend webix.AutoTooltip ?
AutoTooltip is rather simple mixin, that uses onMouseOut and onMouseMoving events of component to show or hide the tooltip.
Instead of extending AutoTooltip it will be more easy to create your own solution based on the mouse events.
Ok, Thanks will create one. 
I have tried to extend the AutoTooltip. like AutoTooltip=webix.extend({},AutoTooltip)
but Tooltip is pointing to the original AutoTooltip event.
Can you put light on this?
It is the timing issue.
While webix.js loading the UI components will define lists of mixins that will be used.
On moment of webix.extend call component already locked the related object ( webix.AutoTooltip ), so the new one will not be used. If it necessary you can modify the object directly by using
webix.AutoTooltip.tooltip_setter = function(){
or subclass the component ( datatable ) directly, redefining the tooltip_setter for the component.
Ok this help Thanks!