TYPO3 Core

In a TYPO3 6.2.4 project, when more than one FAL metadata record is associated with a sys_category, it is no longer possible to save any changes to the sys_category record when it is edited through the Web>List module on the root page. The tab "Items" which lists the relations is always labelled as "not correctly filled in" as long as there is more than one item.
This affects both existing categories as well as categories newly created and filled with relations after upgrading to 6.2.4
As such it is not possible anymore to do maintenance of categories like changing its name, its parent etc while keeping the relations.

This problem did not exist in 6.2.3 and it disappears when downgrading from 6.2.4 to 6.2.3

The TCA in typo3\sysext\core\Configuration\TCA\sys_category.php doesn't set a value for 'maxitems' in the 'type' => 'group' definition for "items".

The change https://review.typo3.org/#/c/27378/4/typo3/sysext/backend/Classes/Form/FormEngine.php which is inclued in 6.2.4 appears to change the default behaviour of getSingleField_typeGroup when maxitems is not defined in TCA.

Keeping the 6.2.4 codebase but reverting this single change makes the problem with editing sys_category go away.