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Planned to improve and fix in 5.1.

If fake Vine is still used and is helpful I will fix the UI (currently broken locally) - which is the reason why I have disabled it at the moment.

Enable Fallback composer from Global Preferences.

Please enable 'Fallback Composer' in 'Global Preferences' from the side menu.

Currently not possible, but I plan to add in multiple usernames per user soon.