Scenario

• I am a VE-preferring user with my editing preference set to "Remember my last editor". I get one edit tab on every page (Single Edit Tab/SET), which is "Edit" or "Edit source" depending on my last editor.
• I visit a talk page where VE is not available and make a comment[1], getting by with wikitext.
• I go back to article editing, and now I have the "Edit source" tab. I need to discover the editor switch to get back to VE.
• This scenario is probably very common on SET-default wikis for new users.

1. The "last used editor" preference appears to get stored as soon as I open the editor, not when I interact or save, which I think is the case on mobile (first interaction?).

Expected

• The "last used editor" preference is never overwritten if only one editor is available on the page.

Note: This only applies to 2017WTE. If you load the 2010WTE directly from the talk page it doesn't change the editor preference.