Can't use developer Tools anymore

[Vasrias]

Hi,
I wanted to use the developer tools today and everything worked fine. Except then suddenly I couldn't edit anything under the developer tabs (I was editing a css file) I clicked every button I could find, hoping to resolve the problem. But instead I closed the document view and can't get it back. I tried the IE developer tools as well and there I have the document view, but can't edit anything as well. For clarification what I mean exactly, I post two screenshots, one of my IE developer tools and the second of my Edge developer tools window.

IE Dev Tools:


Edge Dev Tools:


I hope somebody can help me get back my document view and the ability to edit the sites as well :/
Later I'll restart my pc to see if this helps, but right now I have to much work open. If it helps, I let you know.


edit: The restart didn't help. Same situation. I took a screenshot on my SP3 and marked the toolbar at the top, which is missing, and I can't find a way to bring it back. Additionally, I can't found out, that the left toolbar shows a lot of different files and folders on the page I want to edit, whereas on my pc this toolbar shows only a few (on IE, on Edge I can't access them, because of missing toolbar). I updated the screenshot of my Edge dev windows on pc, so you can see the difference.

Edge Dev Window on my SP3: