Related items (widget) with Plone 5.2 and multilingual

I am trying to get a 'related items field' (defined with XML) to work with Plone 5.2 / multilingual.

If I add a new site and add a new field 'Relation Choice' to a dexterity content type, I can only browse into the first folder (items and folders inside the folder are not shown).

Update: I mean subfolders of first (level) folder

I also tried from Mosaic with schema.Choice and

    <source>collective.themefragments.tiles.CatalogSource</source>

Same happens.
The code worked on Plone 5.1 without multi-languages, and I can see no errors

PS: The related items (behavior) works correctly for the same content item.

Looks like this could be the reason: RelatedItemsWidget and plone.app.multilingual

If you define your schema in code, you could use the same approach as was discussed for the pattern options. https://community.plone.org/t/relationlist-with-start-path/

@provider(IFormFieldProvider)
class IRelatedTeaserImageBehavior(model.Schema):

    related_image = RelationChoice(
        title=u"Related Teaser Image",
        description=u"Add a teaser image",
        required=False,
        default=None,
        vocabulary='plone.app.vocabularies.Catalog'
        )

    image_caption = schema.TextLine(
        title=_(u'label_image_caption', default=u'Image Caption'),
        description=u'',
        required=False,
    )
    directives.widget( 'related_image'
                     , RelatedItemsFieldWidget
                     , pattern_options={ 'recentlyUsed': True
                                       , 'basePath': default_base_path
                                       , 'mode': 'auto'
                                       , 'favorites': default_pattern_options
                                       , 'folderTypes': ['Folder', 'LIF', 'LRF']
                                       , 'selectableTypes' : ['Image']
                                       , }
                     )

alsoProvides(IRelatedTeaserImageBehavior['related_image'], ILanguageIndependentField)

and

def default_base_path(context=None):

    portal = api.portal.get()
    language = ILanguage(context).get_language()

    # this should return the portal if plone.app.multilingual is not installed
    language_root = portal.get(language, portal)

    root_path = '/'.join(language_root.getPhysicalPath())

    return root_path

Unfortunately, I have to do (most of it) it with XML, since that is the only option for themefragments.

Anyway: the TTW adding of fields (Dexterity Content type) is also broken, so I think this is a bug.

I will work around it by using my own custom vocabulary.