Dialog spills off screen if contents doesn't fit

[Matthew Paul Thomas]

Ubuntu 14.10 r135

1. Go to System Settings > "Wi-Fi".
2. If Wi-Fi is off, turn it on.
3. Scroll to the bottom of the list and choose "Connect to hidden network".
4. From "Security" choose "WPA & WPA2 Personal".
5. Tap in the "Password" field.

What you see:
* The dialog title disappears below the status bar.
* The "Cancel" and "Connect" buttons disappear under the keyboard.

What you should see:
* The top of the dialog is still visible just below the status bar.
* The bottom of the dialog is still visible just above the OSK.
* The rest of the dialog contents scrolls in the remaining space.