TYPO3 Core

TCA fields added via ExtensionManagementUtility::addToAllTCAtypes are appended to the showitem list of all types if no explicit positioning (e.g. after:title) has been requested.

By default this appends the fields to the "Extended" tab which is present by default and ready to receive all fields which are simply appended.

However, if one adds a new tab via --div-- without explicit positioning with some fields, all unrelated fields without explicit positioning are now appended to this tab instead. The resulting showitem portion which makes the issue clear:

--div--;LLL:EXT:cms/locallang_ttc.xlf:tabs.extended, --div--;LLL:EXT:myext/locallang_db.xml:mytab, tx_myext_myfield;;;;1-1-1, unrelated_field

The new tab with the field tx_myext_myfield was simply appended to the showitem list, thus preventing the "Extended" tab from being the last. The unrelated_field is now placed in the new tab.

A temporary fix is to set a explicit position for the newly added tab; this ensures that the tab and its fields are not simply appended and leaves the "Extended" tab on the last position.

The real fix however would involve explicitely placing all fields without explicit positioning in the "Extended" tab. This way arbitrary tabs could be appended without unrelated fields showing up in them.

This issue affects all TYPO3 CMS versions.