TYPO3 Core

In the info module there the "Pagetree Overview" that shows a tree of pages with the selected page as root. You can click on several pencil icons there to edit either a single page or mass edit a particular field of all pages currently shown in that tree.

As soon as the root page of that view is the actual root page (0) of your real page tree, both the pencil icon of that particular page and the mass editing of all fields throw an exception.

Uncaught TYPO3 Exception
#1437656456: $uid must be positive integer, 0 given (More information)

IN CMS 6.2 there is just an error message instead of an exception, so the rest of the actions will be executed as expected.
Just the root page is excluded from the list of mass editing form fields then, which is what I would expect in CMS 7 as well.