Add undo functionality / show history on validation interface

[aileenzeng]

From #1384:

3. Need to allow users to go back (in case people make mistakes)
   a) History drop-down? (See all labels they've done this mission?) (Jon's note: I didn't say 'drop-down'--basically, I was suggesting a ribbon-like interface that would continuously update and show the ~5 most recent validations--which you could return to. This has dual benefits: one, it shows the user what they just validated (confirming the validation action) and second, it could be used to go back to a previous validation and change it)
   b) Undo functionality for labels

[jonfroehlich]

IMO, this should be a lower priority for now. Let's see--via user testing--whether users really feel like this is a necessary feature.

[jonfroehlich]

I still like the ribbon-based idea to show recent validations and allow user to change mind or update info. Could show ribbon in validation interface and also recent validations on dashboard.

[jonfroehlich]

I still think this is a reasonable idea.

We just received an email:

I hope you are doing well. On my 2546 or 2547 label, I accidentally selected disagree when it should have been agreed. I'm not sure how to go back to the previous scene, so if there is anything that I can do on my end to fix this, please let me know. So sorry for the inconvenience.

I responded:

This happens semi-frequently to me too (about once every ~100 validations or so, I click the wrong button).

Thanks for letting us know. In the future, we'd like a way for folks to review their validations and make corrections but we have no such feature yet.

[crescendochu]

During the Oradell Mapothon today, I accidentally disagreed with a correct label and realized there is no way of going back. Maybe we should have a back button somewhere? Helping users to recover from mistakes is one of Nielsen's Usability Heuristics. :)

[jonfroehlich]

I really wish we had this. Just "agreed" with a curb ramp label on a driveway in Newberg. I wrote in correct description but selected wrong button.

[misaugstad]

@srihariKrishnaswamy I'm really excited to have you working on this! I think that it's best to just have the undo button go back to your most recent label. I don't think that we need to worry about anything further back than one label. This should make implementation easier, it should keep the design more simple, and I believe that it should handle the vast majority of cases.