This is a UI nitpick.
Problem: Expected “convert webarchive to text” command is available in documents menu, but not in the popup menu.
Where: Scrivener 1.0RC5
Reproduce: Import a webarchive. Select the webarchive in the navigation column. Clicking on “Documents” menu reveals the “convert webarchive to text.” CTRL-clicking on the webarchive in the navigation column does not.
Image - normal option:
Image - missing from menu:
[/img]
This is clearly not a bug, but a wishlist item. 
The pop-up menu only provides the most commonly used items. There is no way it is intended to replicate the whole of the Documents menu - such replication would be silly, negating the utility of such a pop-up menu in the first place. “Convert webarchive to text” surely falls into the less-used category for most people.
Best regards,
Keith
Sorry - thought I had scoped the forums, but didn’t see there was a separate wishlist forum. This should probably be moved/deleted.