Easy to lose wiki work by pressing wrong "Edit" button

When editing the wiki, if you switch to "preview" mode, the button changes its label to "Edit". At this point there are two buttons labeled "Edit" on the screen. One will switch you back to edit mode. The other will throw all your work away.

I realize it should be easy to tell them apart, but if you're moving too fast, it's really easy to hit the wrong one.

Possible solutions:

• Make the pressed "Edit" toggle button do nothing when clicked (already editing!)
• Relabel one