That has never been a standard feature in Firefox. Now, either the add-on which added that feature to your Firefox is disabled or it is incompatible with Firefox 30. Take a look at your extensions to see what you have installed and see if it is disabled. If not, right-click that extension and use Find Updates. If it still doesn't work use the More ... button and look for the Homepage (not all extensions use that feature provided by Mozilla) and see if there is Support information or an email address to contact the developer of that extension. It is up to each add-on developer to keep their stuff up to date and to support their stuff. Most add-on developers do a good job in that respect, but some only provide the add-on without providing support and might be slow to update it as needed. If that is a popular extension "we" might be able to hep you, but we would at least new the correct name and maybe the URL of where it can be downloaded.

Yes Yes, I only needed to install newer version of add-on. Now it's working again. THANK YOU :)