I’m very sorry for my bad English, which is not well explained. But it wasn’t the save/open menu from FireFox itself but the button from websites.
OK, let’s try to open Facebook and upload a picture from it , also after pressing the upload (screenshot attached) a dialog window should pop-up to browse thru the files which are stored on the computer but instead after pressing the upload button nothing appears, nothing happens. I really don’t know whether Avast is blocking some flash or java script’s here.
http://i.cubeupload.com/mHn4wH.jpg
I had uninstall Avast and it works again, re-install and it won’t work again until i downgrade Fire Fox to version 26.0 and all is fine.
But then i re-answered an open a bugzilla report which had the same case and some dev’s said that it would come from Avast.
But thanks to start trying to help me, very appreciated. 
PS : I had found this earlier on Avast forum’s which was mostly with Flickr, Photobucket and few other websites that are behaving like this.
PS II:My English is bad but hopefully it could be read. (in some way)