Comment 5 for bug 1068304

Confirming on Ringtail as well.

Solution: make sure you have a public key file in ~/.ssh

Create it with ssh-keygen -y from your private key if you don't have the public key in a separate file.

If key.pub is available, gnome-ssh-askpass pops up and asks for the passphrase.

Without the key.pub, gnome-ssh-askpass doesn't pop up even though the private key file is there.