The problem isn’t solved yet! The bug is still there -.-
And I found a new one:
After I clicked on my file under the Save files, it said “Saving project… (Sending files to server)” and then “Save failed: Files not uploaded: Upload failed, please check your internet connection”! My connection was stable though!
Edit: And I got this error: “Not logged in: Could not log in, timeout expired”! And I lost a whole lot of work!!