Hi DaNish Ali.
Thanks for your hint regarding the Firefox plugins.
Indeed, I have installed the “Blur” add-on (formerly “donottrack”). Once, I disable this plugin, the facebook like box is displayed under Firefox.
The Internet Explorer does not have such a plugin installed.
Any chance of circumventing the Blur addon? If active, it simply displays the title of the widget. Once Blur is active, that results in having a title displayed on the website and nothing else. Of course, that title header makes every user trying to click it. Since it is not clickable, nothing happens.
As a workaround, I have removed the title. So if someone uses Blur, at least there is no irritating title ??