TYPO3 Core

1) When you open a click menu by a right-click on a content element and choose the 'Create New wizard' option, you can create an element just fine.
But wenn you close the new element it just loads an empty content frame in the backend.

2) When you open a click menu by a right-click on a page in the page tree and choose the 'Create New wizard' option, you get an exception after choosing a position:
Argument 2 passed to TYPO3\CMS\Backend\Form\AbstractNode::mergeChildReturnIntoExistingResult() must be of the type array, null given,
called in .../typo3/sysext/backend/Classes/Form/Container/PaletteAndSingleContainer.php on line 152