Classic editor weird appearence

I haven't posted on my website in the last two weeks, and all of a sudden i see my classic editor like this:


Any text that i copy/paste to my editor it turns like this, it looks like a have two classic editors but on the second one i can't scroll and see the rest of the text.
Does anyone have a fix for this?

Thanks

I got it fixed, the problem was from my browser(firefox developer), i just installed normal firefox and everything is good again.