Confusing user error when attempting to save changes that cancel each other out.

What steps will reproduce the problem?
1. Save a new exploration (any content).
2. Edit a state's content (example, from "test-content", to "test-content2")
3. Edit the state's content back (to the original "test-content")
4. Try to save.

What is the expected output? What do you see instead?

Expected:
Option 1) Oppia to recognize no changes have been made, and thus not allow me 
to click Save in the first place.
Option 2) Oppia to allow me to click Save, even though no changes have been 
made.

What happens instead:
- the green Save Changes button at the top shows an increasing change counter 
changes, and appears to be inviting a save, when no changes are actually 
present. (screenshot attached)
- clicking Save, presents an orange error message "Warning! Your changes cancel 
each other out so nothing has been saved.",  yet the green "Save Draft (2)" 
button remains.  (perhaps we should reset it if/when this error is triggered?)

Original issue reported on code.google.com by anu...@google.com on 11 Jun 2015 at 9:30

Attachments:

[Screen Shot 2015-06-11 at 5.28.27 PM.png](https://storage.googleapis.com/google-code-attachments/oppia/issue-817/comment-0/Screen Shot 2015-06-11 at 5.28.27 PM.png)

danieljjh / oppia

Confusing user error when attempting to save changes that cancel each other out. #817