Issue: Setting Area Content Types

I've noticed two issues when trying to configure the content types allowed in an area.

1. If I save 'all' as an option, I'm unable to later deselect this option and choose a specific content types in its place. If I uncheck it and select just 'page' in its place, the change does not actually save. Going back into the area setup, both 'page' and 'all' are selected and all types can still be created.

2. I'm not sure if this is how it's intended to work, but it's definitely tripped me up a few times that I wonder if it's a bug. It seems like 'page' is a prerequisite for some other content types to work. For example, if I try to set an area to only allow 'book' types, attempting to create a book in that area just gives me this error:


However, if I select page + book as area content types, then I can create a book with no issue. I've noticed this also happens for categories, templates, and attachments so far.

I've tried to setup an area that allows only books, so that if somebody wants to add a new chapter to that book, they have to select a different area to save that book to since the current area in the select list, I assume, would be grayed out in that situation. But that doesn't currently work, since I can't even create a book in that area due to the error message above.