facebook problems

I noticed strange behavior with facebook plugin on the sidebar.
I directly put the code, taken from facebook developer site, in text-widget.
It work fine but when I resize the windows the plugin blinks continuously especially if I use the Firefox view responsive layout tool (ctrl+shift+m).
This may not be a problem(users not need to resize windows) but a friend of mine told me that he saw some weird behavior on his Mac width Chrome browser also without resizing.
I cannot put the link to the site in question because it is still under maintenance
thanks