Aside disappear suddenly - Never seen this issue

I'm currently creating a website, which has an div called Aside. This is basically an aside part of the website.

I'm including it to my index.php.

There is nothing serious about it, however I have a huge problem. I have had everything working yesterday. Today when I visited the website in my Firefox browser, I have just happened to see that the Aside div has completely disappeared. When I get Firebug to inspect the Aside div, it show me that div greyish. So I guess it means that it is not displayed.

I have searched for every "display:none" in my document, but I didn't find any which relates to the Aside div.

I have tried it in Internet Explorer and I got the same problem there as well. However I have tired it in Chrome and it has worked prtyy well, it showed everything.

Than I have tried it in my Virtual machine's browsers and all the 3 browsers were showing the aside div.

I have also tried it on my VPS and it was okay there too!

So what the hell could happen with my browsers or my code, that it does NOT display ONLY the aside div? What can be the problem?

I have never seen anything like that, because it was okay yesterday and today its bad...

Any help would be appriciated.

And I have also tried to delete my history and everything, but its the same.

Disable AdBlock / AdBlock Plus in your copy of Firefox, or give the div another ID / class as a quick fix. The reason I thought of this first was because I had a much more blatant ID of "advert" on a div which I only noticed got blocked in a copy of Firefox which had AdBlock Plus installed when I was testing the site out.

A more permanent fix, if you intend to keep using AdBlock, would be to remove the name of the div that got blocked from the list of keywords / filtering rules that you're using.