TYPO3 Core

I was following a tutoriak by kasper on modern template building everything was going on well until I came to the part of setting up a template storage under the root level but after creating it and saving it, the middle frame disappeared and I tried several times to get it back but failed. I even reinstalled the dummy package and followed the whole tutorial again but when i set up a temporary storage the middle frame disappears.

(issue imported from #M8)