Steps to reproduce the issue

1. New installation of Joomla 4.3.1
2. Delete the main system category "uncategorized", works without errors or an alert, that at least one (system-)category should be present.
3. The recreation a new/main category of your choice leads to the following error:

An error has occurred.
0 Joomla\CMS\Toolbar\Toolbar::versions(): Argument #2 ($itemId) must be of type int, null given, called in /home/httpd/vhosts/WHATEVER/administrator/components/com_categories/src/View/Category/HtmlView.php on line 239

Call stack

1 | () | JROOT/libraries/src/Toolbar/CoreButtonsTrait.php:511
2 | Joomla\CMS\Toolbar\Toolbar->versions() | JROOT/administrator/components/com_categories/src/View/Category/HtmlView.php:239
3 | Joomla\Component\Categories\Administrator\View\Category\HtmlView->addToolbar() | JROOT/administrator/components/com_categories/src/View/Category/HtmlView.php:121
4 | Joomla\Component\Categories\Administrator\View\Category\HtmlView->display() | JROOT/administrator/components/com_categories/src/Controller/DisplayController.php:111
5 | Joomla\Component\Categories\Administrator\Controller\DisplayController->display() | JROOT/libraries/src/MVC/Controller/BaseController.php:678
6 | Joomla\CMS\MVC\Controller\BaseController->execute() | JROOT/libraries/src/Dispatcher/ComponentDispatcher.php:143
7 | Joomla\CMS\Dispatcher\ComponentDispatcher->dispatch() | JROOT/libraries/src/Component/ComponentHelper.php:361
8 | Joomla\CMS\Component\ComponentHelper::renderComponent() | JROOT/libraries/src/Application/AdministratorApplication.php:143
9 | Joomla\CMS\Application\AdministratorApplication->dispatch() | JROOT/libraries/src/Application/AdministratorApplication.php:186
10 | Joomla\CMS\Application\AdministratorApplication->doExecute() | JROOT/libraries/src/Application/CMSApplication.php:293
11 | Joomla\CMS\Application\CMSApplication->execute() | JROOT/administrator/includes/app.php:61
12 | require_once() | JROOT/administrator/index.php:32

Expected result

Category recreation from an empty DB-table should work without problems.

Actual result

Category recreation is impossible.

System information

Joomla 4.3.1, PHP 8.2.5

Possible solutions

1. Comment out line 239 in administrator/components/com_categories/src/View/Category/HtmlView.php >>> Category recreation works without any problems.
2. Alert user, that at least one main category must be present, make it impossible to delete this category.
3. Any better solution you propose :)