Enable web editing of simple text document in shared folder

[s-light]

i think this could be a bug for the app files_texteditor app itself.
as it is a owncloud app i post it here first…
i think it is reported as [enhancement] enable editing to anonymous users #186
and partly related to Collaborative realtime editing for text files #167

Steps to reproduce

1. create folder
2. share folder via public link - allow editing
3. create simple txt file
4. write some text in the pop-up-editor
5. access public link from a private browser tab
6. enter password
7. try to edit the text file
8. it only allows to download the file. no web-editing possible.

LibreOfficeOnline is installed - with a writer document it works.
(but this is no option as the LOOL app does not work on mobile…)

Expected behaviour

simple text-editor opens and allows editing

Actual behaviour

only download possible

Server configuration

ownCloud version:

installed	1
maintenance
needsDbUpgrade
version	10.6.0.5
versionstring	10.6.0
edition	Community

List of activated apps:

myuser:~$ occ app:list
Enabled:
  - activity: 2.6.0
  - calendar: 1.6.4
  - comments: 0.3.0
  - configreport: 0.2.0
  - contacts: 1.5.5
  - customgroups: 0.6.1
  - dav: 0.6.0
  - drawio: 0.0.9
  - federatedfilesharing: 0.5.0
  - federation: 0.1.0
  - files: 1.5.2
  - files_external: 0.7.1
  - files_mediaviewer: 1.0.4
  - files_pdfviewer: 0.12.1
  - files_sharing: 0.14.0
  - files_texteditor: 2.3.1
  - files_trashbin: 0.9.1
  - files_versions: 1.3.0
  - firstrunwizard: 1.2.0
  - guests: 0.9.1
  - market: 0.6.0
  - metadata: 0.10.0
  - music: 1.2.0
  - notes: 2.0.6
  - notifications: 0.5.2
  - provisioning_api: 0.5.0
  - richdocuments: 2.4.1
  - search_elastic: 1.0.0
  - systemtags: 0.3.0
  - tasks: 0.9.7
  - templateeditor: 0.4.0
  - updatenotification: 0.2.1
Disabled:
  - admin_audit
  - announcementcenter
  - encryption
  - enterprise_key
  - external
  - files_antivirus
  - files_classifier
  - files_external_dropbox
  - files_external_ftp
  - files_ldap_home
  - files_lifecycle
  - firewall
  - graphapi
  - oauth2
  - openidconnect
  - password_policy
  - ransomware_protection
  - sharepoint
  - systemtags_management
  - theme-enterprise
  - user_external
  - user_ldap
  - user_shibboleth
  - windows_network_drive
  - wopi
  - workflow

Client configuration

Browser:
Firefox 88.0.1 (64-bit)
Operating system:
Kubuntu 20.04