Following a conversation with naftali5, we came up with a new GUI concept that would probably make the seperate modes obsolete, and simplify users/devices.
The new GUI should have two pages: "extensions" and "devices". Devices is the same as the devices page as it exists now. "Extensions" is similar to the current extensions page, but at the bottom, it should show a list of all the devices assigned (fixed) to that extension. When creating a new extension, there should be a checkbox (checked by default) "Create a new device for this user".
It would be possible to edit a device from either place, but if you're not using adhoc devices, you can effectively ignore the Devices page, and just use the extensions page to manage everything. Optionally, we could make it so in EXTENSIONS mode, the device page is simply hidden, but that probably isn't necessary.
The benefit of this - besides getting rid of the two GUI modes - is that more people running in EXTENSIONS mode would be made aware of the fact that you can have more than one device per user, and it would be a lot easier to manage.
This should probably be done as part of the DevicesTakeTwo changes.
