Combo in Grid Events Go to Grid and not Combo

Ok, I think I finally got the jist of the event model. When you have a combo in the grid, and the grid column is editable, it is the grid and not the combo that gets the events.

As far as I can tell if the grid is not editable there is no event that fires when the user types, making searching the list not possible.

So the main question is how do I get the object id of the combo box in the column from the onCellTextChanged event?

And a secondary question, where can I go in the source directory to find the event creation for any give object, the onxxx names do not seem to appear in the source?