Cannot directly click manual login entry in Unity Greeter

I have my greeter configured with three user seat entries visible (users 1001-1003) and also the manual Login enabled to allow user 1000 access as well (though that user's ID does not appear as a separate entry in the greeter). This is my preferred setup.

I find that I cannot directly mouse click the manual login unless the last user entry has focus. If either of the first two user entries has focus, clicks on "Login" are ignored. One must execute two mouse clicks to access the manual login. One to focus the last user ID in the list, and the second to access the manual login. Of course keyboard arrows also work to gain access and/or focus the last user name.

It's a small thing, but it would be helpful if the manual Login could be "clicked into" regardless of the focus state of the other visible greeter seats.

Is there a parameter controlling this that can be adjusted?
Is it intentional or a bug?

Ubuntu 14.04 x64
Nvidia geForce GT 730 (proprietary drivers 340.58)