Ok, I verified that all of things you mentioned were implemented correctly, still seeing same problem. To duplicate issue, here are the steps I took :
1. Browse to page with the grid control.
2 . Click on the "Edit" icon next to the second item in the list; at this point, the item goes into edit mode as expected, showing editable textboxes for all the fields.
3. Without changing any of the values or clicking into any of the textbox fields, dismiss the editing template by clicking the "Undo" button.
4. Click on the same "Edit" button for the same row (2nd item) clicked on in step 2.
6. If however, I click on another rows "Edit" button, I can edit it - BUT, if I dismiss, then click the Edit button again, same thing happens.