Just downloaded the demo, looks like it's still an issue. A bit disappointing.
I definitely think this should be addressed. It makes no sense to have everything indented with tabs except list items. The tab/space issue in general seems to strangely conspicuous considering how mature an application WeBuilder is. Even with 'contrain text to cursor' enabled you can still click in the middle of a tab, which can screw up using the add/remove indent functions.
IMO if 'use tabs instead of spaces' is enabled then there should be absolutely no cases of tabs being treated as if made of spaces, including when clicked on with the cursor.