I postponed a recurring task but I'd like to switch it back. Could we have an undo for the postpone instead of re-typing the recurring due date?
After postponing a task there should be a bar allowing to undo the action for a short time. If you postpone in the 7 days view, the task will be hidden so there is no fast way to undo your action.
On iOS, a often-used way to undo actions is shaking the device. I found this to be a nice unobtrusive solution!
On other mobile platforms, this would work as well, but I am not sure it is that common and intuitive.
On non-mobile platforms, there is more room for undo buttons / messages etc.