While you can undo editing fields, to recover the previous values, once you click a reset button (button[type=reset] or input[type=reset]), you loose any change. This might lead to massive data loss if the reset button is activated by accident. It would be great if the reset action were stored in the undo/redo stack.
It sounds nice. We have a feature to save/restore form control state. See WebCore/html/FormController.{cpp.h}. It might be reusable for the undo/redo stack.