Hello,

components/UserSelect.qml uses this logic for choosing between a login textbox
or a list of users:

    property bool  showUserList: (usersList.model.count &&
usersList.model.disableAvatarsThreshold) ? usersList.model.count <=
usersList.model.disableAvatarsThreshold : true

However, this logic has some problems. If there is no user, it still shows the
(empty) user list (as usersList.model.count == 0 == false).
Also, usersList.model.count cannot count when network authentication is in use.

I think that this theme should allow the user to select between the two
aproches (user list or login textbox) at runtime. Something like an extra dummy
avatar with "Authenticate as another user". Also, the last used login should
always apear at first (and pre-selected), even if it is not a local user (that
would not normally apear in the user selection). Ex:

+----------+  +---------+  +----------+  +----------+
|          |  |         |  |          |  |          |
|  user 2  |  |  user 1 |  |  user 3  |  | login as |
|   last   |  |         |  |          |  | another  |
|   used   |  |         |  |          |  | user     |
+----------+  +---------+  +----------+  +----------+

             +-----------------+ +------+
             |*********        | |enter |
             +-----------------+ +------+

And when user click on "login as another user":


+-----------------+
|login            |
+-----------------+

+-----------------+ +------+
|*********        | |enter |
+-----------------+ +------+

+------+
|back  |
+------+

With "back" or "ESC" returning to the user selection.

It would be interesting to have an option to disable each behavior as:

ForceManualLogin: goes directly to login/password and disables the "back"
DisableManualLogin: hide "login as another user"