Q:

Has Anyone faced this Problem: In-Browser code editor not working

Today when I tried opening my page. I'm getting it as

for both visualforce and apex class. Don't know why? 
I have to go to the individual page and class to modify any changes and it's disgusting
Any Solution for this. Tried with different Browsers and the same issue in all of them

A:

You need to clear the browser cache and cookies.  Read this for more info: Where did the line numbers go (browser editor)?