TYPO3 Core

i can confirm that

TCEFORM.pages.categories.config.treeConfig.rootUid = XXX

works in TYPO3 6.2 but not anymore in 7 LTS.

Also it is not possible to overwrite this setting:

TCEFORM.pages.categories.config.treeConfig.appearance.expandAll = 0

Confirmed in TYPO3 7.6.2. Probably related to #73209

As Stefan saied, this seems to work. But now it will even not work with 6.2.19.
If I set

TCEFORM.pages.categories.config.treeConfig.rootUid = 123

I get a fatal error while trying to edit page properties:

Uncaught TYPO3 Exception
#1: PHP Catchable Fatal Error: Argument 2 passed to TYPO3\CMS\Backend\Utility\IconUtility::mapRecordTypeToSpriteIconClass() must be an array, null given, called in /html/typo3/typo3_src-6.2.19/typo3/sysext/core/Classes/Tree/TableConfiguration/DatabaseTreeDataProvider.php on line 252 and defined in /html/typo3/typo3_src-6.2.19/typo3/sysext/backend/Classes/Utility/IconUtility.php line 841 (More information)

TYPO3\CMS\Core\Error\Exception thrown in file
/html/typo3/typo3_src-6.2.19/typo3/sysext/core/Classes/Error/ErrorHandler.php in line 101.

Additional this config, which should only use categories fom a folder with ID 123, will not work, I see all categories from all pages.

Supplement:

If you add the ID of a category in pagetsconfig of a rootsite, in 6.2 you will get only this category and children

TCEFORM.pages.categories.config.treeConfig.rootUid = 5

But if you add something like this:

TCEFORM.pages.categories.config.treeConfig.rootUid = 5, 6, 7

you will only see category with UID 5 and Children, but not 6 and 7.

This whole stuff will NOT work with TYPO3 7.6.4

If you chose an ID for a catogory which does not exist in 6.2, the fatal error occurs, please see the error message above, and you can not edit the pageproperties, because of this error.

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/47083

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/47083

Patch set 4 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/47083

Patch does not work for me in 7.6.4

Other TCEFORM configurations like 'description.disabled = 1' works.

Patch set 5 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/47083

Patch set 1 for branch TYPO3_7-6 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/47799

fatal error still occurs while trying to edit page properties on TYPO3 7.6.12,
please reopen this task.

#1: PHP Catchable Fatal Error: Argument 2 passed to TYPO3\CMS\Core\Imaging\IconFactory::getIconForRecord() must be of the type array, null given, called in 
/home/praca/source/typo3_src-7.6.12/typo3/sysext/core/Classes/Tree/TableConfiguration/DatabaseTreeDataProvider.php on line 268 and defined in /home/praca/source/typo3_src-7.6.12/typo3/sysext/core/Classes/Imaging/IconFactory.php line 131

Rafal Brzeski wrote:

fatal error still occurs while trying to edit page properties on TYPO3 7.6.12,
please reopen this task.

[...]

Rafal, are you sure you have set an existing category id? We also got this fatal error, but realized we just defined a non-existing id.