OOPS,  Sorry have found the answer here

http://devcenter.infragistics.com/Support/KnowledgeBaseArticle.aspx?ArticleID=6160

below was the original question but the answer was found above.......  ie. use Cell update itself ....

&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 

 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Arrrrr.

The checkbox in a grid - when checked - does not seem to fire an beforeupdate and afterupdate event.
i.e. only after the cell is de-selected does the BeforeCellUpdate event fire.

 i.e. in MSAccess a check on a checkbox will allow you to popup a msgbox and then cancel or not cancel.
 But in UltraGrid it does not.

How do you get an event to happen as you change the state of the checkbox when in a grid?

I was going to attach a Northwind example but do ot see how.  I cropped the Northwind Product table onto a form and it already has a discontinued column.   In the Ultragrid I changed to style= checkbox and Value was already boolean.