Delete key closes my widget even when cursor is visible in field.

What steps will reproduce the problem?
1. Write in a Rule field.
2. Click somewhere on that browser page, outside of the field.
3. The cursor is still visible, although it has stopped blinking (which I did 
not notice)
4. I was in the middle of deleting a word.
Since my cursor is still by that word, I expect that if I press "delete" I will 
delete the letter where my cursor is.
5. My widget window disappears. :(
6. I realize that my cursor was not inside the box, but that I had the browser 
page selected
7. I re-open the widget I was working in.
8. All of my changes were lost. :(( I ended up deleting everything, instead of 
deleting a letter.
9. The Rule reverts to the last-saved text.

What is the expected output? What do you see instead?
I expected pressing the delete key would delete the letter, and not turn into 
the browser's back button. I expected this becasue I could see my cursor in the 
field where I had been typing. I just did not realize it wasn't actually 
"there."

What operating system are you using?
Yosemite v 10.10.3

Please provide any additional information below.
Thanks!

Original issue reported on code.google.com by sba...@google.com on 14 May 2015 at 11:02

danieljjh / oppia

Delete key closes my widget even when cursor is visible in field. #757