Comment 15 for bug 545859

Following the idea that the authorization was finishing ok but the button was not visible I manage to try this and it worked for me:
sudo gedit /usr/share/gwibber/ui/gwibber-accounts-dialog.ui
Go to line 276 and insert the following line (this will align the Cancel/Add button to the top, avoiding it to go outside the view area).
<property name="yalign">0</property>
Save and try to add the facebook account once again.
Hope it helps.