The device tree contains all of the devices in a list form; they are by default listed by type.
The search field allows you to find devices by name, brand etc., if you are unsure of where to find it in the listing.
Connection allows you to show devices by specific connection type, e.g. LAN, RS232, I/O. All of the connections are enabled by default. Approval allows you to show devices that are only Neets approved, user approved or not approved. All of the approved types are enabled by default. Sorting allows you to sort the list by type, manufacturer or modified date. This list shows type by default.
The favorites box allows you to add your most used devices, manufacturers, etc. as a favorite, so that you have quick access. To add favorite, right clicking on a device or manufacturer, and then choose the add to favorites option.
This button allows you to save your own layout of the device tree as a default, reset to previous default settings or reset to factory defaults.