UI is useless if having two monitors and using just the external one

[Alexander Adam]

When I am home, I put my notebook on an external monitor and just use this one.
While this causes already pain since 14.04 [1], I noticed that the UI for the login is absolutely useless for someone who doesn't how the multi-monitor-functionality on lightdm works.

If the integrated monitor is off and I am just using the external one, lightdm "shows" the login screen on the integrated monitor anyway (the login screen is therefore invisible).

What I can see in this moment is just a screen with the Ubuntu logo. No cursor, no message and nothing else that could tell the user that he can login now.

So even if the behaviour, that the login screen would be shown on the correct monitor, it would be useful to give the user a hint how he could login (while it could be that he is looking on the wrong monitor).

For example an arrow on the edge which indicates where the cursor is. So if someone moves the mouse he will see, that the mouse still works (which isn't the case now).
And somehow it should be communicated, that the login screen is on another monitor (something which says "hey, the login screen you are looking for is on the left side, so you have to move the mouse cursor on the right side if you want to see it.").

[1] https://bugs.launchpad.net/ubuntu/+source/unity-settings-daemon/+bug/1310745