Just a reminder the login will be different because it corresponds to the user preferences and what you watched to match the account. The General shows general since there is no login to give it what settings you set or movies you watch to give the AI what it display to Login vs No Login. This isn't a FireFox but how youtube AI tracks the registered account vs no login for it to track your habits.

In youtube account what settings should i change? I think this is related to FF. In chrome i have n't such this design issue.

I think both does the same for No Login and Login accounts it's AI is going to configure based on the login account and what you watch or videos you click on. In YT find your settings and see what is different in the settings.

Place of Description under the video is the problem. Look at datetime under the video after login. Description should n't be next datetime. I really do n't know why description has moved next datetime of viceo. Description should be under SUBSCRIBE red button BOX, Not be next datetime. After login it has moved & has stuck on datetime. I changed my resolution > Not help I disabled hardware accelerator > Not help

These two links helped me on this issue : Link 1 Link 2 Problem is not from FF, This is new layout of YouTube > New layout is totally crap.