There's 2-3 different ways to configure the screens...
- use xrand
- use arandr (or the frontend made by elive, which shows up in the applications menus)
- use the native E27 screens configurator
NOW, IMPORTANT: something important to know: by default only the third option is valid (native E27 configurator), if you try to configure it with another tool it may not work, or the native-configurator may try to put back its defined settings on it.
We should make some betatestings about these multiple things in order to see all the possibilities and compatibilities
Elive has not yet decided which tool to use by default: so the friendlier may be the one from the applications menus, but the native one should be the correct since it can include better features, triggers, autodetections, etc...
BTW: I just wrote this to help the reporting of bugs of Enlightenment and to have a more stable and featured desktop ready sooner!