Not sure if this should be filed under VisualEditor or Translate.
When clicking the "edit source" button on a translation or a page that uses the Translate extension, it isn't possible to edit the wikitext directly; instead, the user is told to use the Translate extension to change the content.
When clicking the "edit" button on a translation of a page that uses the Translate extension, it's possible to edit the text with VisualEditor. At first, I thought this was a feature, and that changes would be propagated to the Translate extension, until I tried to save the page and got the following error:
Error saving data to server: Unsuccessful request: Unknown error: "tpt-target-page".
If VisualEditor can't be used to edit those pages, it probably shouldn't lead users to believe it can :)