From time to time, when using Galeon, my cursor gets stuck in drag mode. An old bug report exists about it on Launchpad but doesn't seem to have been reported upstream.
Last week blino told me about a workaround he found when it happens to him in Firefox or Epiphany: activate the menu with Alt+F.
This works in Galeon too! I no longer need to switch to tty1 and kill Galeon!