Missing Add-Button for limited sites

[rusty-snake]

trafficstars

Before submitting a bug report

• [X] I updated to the latest version of Multi-Account Container and tested if I can reproduce the issue
• [X] I searched for existing reports to see if it hasn't already been reported

Step to reproduce

1. Create a container
2. Open MAC Menu (toolbar icon)
3. Go to manage containers (bottom of menu)
4. Click on container
5. enable limit to specific sites
6. manage list of websites

Actual behavior

white void, no button/menu/whatever to add sites here

Expected behavior

An + button or an text input field.

Additional informations

reproduced with clean firefox profile

Provide a copy of Troubleshooting Information page (optional)

No response