I found a problem in one of my applications under the 1.2.0 release with using revert().

In this simplified code, I create a grid with a ItemFileWriteStore behind it. If I edit the data in the grid, and then call revert(), the edits are reverted correctly. If I create a new row using store.newItem(), and then call revert() immediately, the new row disappears. But if I create a new row and THEN edit the field in the new row, when I use revert() my Grid disappears and says "Sorry, an error occurred." This behavior is consistent across FF2, FF3, and IE7.