Connecting to CalDAV only show one calendar #42

Before submitting

• I've searched existing issues and this isn't a duplicate.
• This is a reproducible bug in Calnode — not a configuration/setup question or a feature request.

What's the bug?

I'm using Calendar app with Synology. When I connect to it through Calnode it only show the "primary" calendar and none of the others. Also the Check/Book inputs are confusing and the "book" can't be unchecked.
With any other app using the exact same login it does show me all the calendars I have in my account.
I should be able to choose which calendar to use.

Steps to reproduce

Calendar -> Connect a calendar -> CalDAV (Apple iCloud, Fastmail, Nextcloud)

Provider: Nextcloud / other (cusom URL)
Server URL: https://caldav.example.com
User: X
Password: X

Calnode version / commit

v0.9.0

How are you running Calnode?

Self-hosted — Docker

Logs, screenshots, or anything else