Steps to reproduce:

• create a page with an extension tag for which VisualEditor does not have special logic, and which has some parameter (e.g. <templatestyles src="Foo"></templatestyles> - avoid self-closing syntax which is handled more incorrectly (T177180))
• edit the page in VE
• click on the extension tag (<> icon) then the Edit button
• edit the src field

The "Done" button will not become active - apparently it only listens to changes in the main content, not in the parameters.

See also:

• T177180: VisualEditor handling of self-closing XML-style extension tags is buggy (Cannot read property 'slice' of null)
• T177183: VisualEditor handles XML-style extension tags with no content incorrectly