Fix strange 0's

[kepstein23]

After merging main, there are some strange zero's popping up, and I'm not sure why. I'm fairly certain that this 0 corresponds to the stage index.

The first issue is that the button text on the add element popup is a 0, as shown below:

The second issue is that after adding an element a "0": is appended to the beginning of the code editor as shown below:

Successful completion of this issue involves the following

• [ ] button text on the add element button being something meaningful
• [ ] adding an element should not add the 0 to the beginning of the treatment