Where is the persistent option for Startup Disk Creator in 16.04?

Unfortunately it looks like in the source release notes changelog it was a decision to drop the Erase and Persistence widgets:

usb-creator (0.3.0) xenial; urgency=medium

  [ Marc Deslauriers ]
  * Rework the whole imaging process for writing to devices:
    - Use an equivalent of dd to make an exact copy of the image to the device
    - This also breaks persistence.

  [ Mathieu Trudel-Lapierre ]
  * Update UI and frontend code to drop the persistence widgets.
  * Drop Erase Disk widgets too.

 -- Mathieu Trudel-Lapierre <[email protected]>  Fri, 11 Dec 2015 12:37:41 -0500

This can be found if you download the source for usb-creator-gtk.