Adding field to @@personal-preferences

Does anyone have any examples or can point me to how to add fields to @@personal-preferences (without over-writing other personal/user properties) ?

  <adapter
      factory=".personalpreferences.PersonalPreferencesPanelAdapter"
      provides=".personalpreferences.IPersonalPreferences"
      for="plone.app.layout.navigation.interfaces.INavigationRoot"
      />

Just an idea. I think with a custom adapter, you can define another schema. The custom schema can inherit from IPersonalPreferences and then have additional fields.

Seems so:

Thanks, I gave that (and some other suggestions I found) but I could not get it to work.
I have not tried to use 'override' yet, since I hope to avoid that if anyone else 'likes the add-on'. Will try to give it another try later.

In the README of plone.app.users there it says you can extend the userschema.xml in your genericsetup profile. See GitHub - plone/plone.app.users: User registration and profile forms for the Plone CMS ... definitely something missing in the documentation.

Currently, userschema.xml can be used to customize the user profile form and registration form, but not the user preferences form.