Teachers can set student avatars, instead of behavior characters. When this mode is enabled, milestones will not be shown at all. Here's how.

1. Go to the class page and click the Settings icon in the top right
2. Click Edit Settings
3. Go to the Interactions tab
4. Under Theme, click the only option.
5. Choose Student Avatars (no milestones)
6. Click Save
7. Your behavior page now shows student avatars, instead of characters.