The main panel is where you load complete sample patches. It also contains the “global controls”. These are controls that affect and modify the sound of entire patches rather than the individual key zones.The remote editor panel is where you load individual samples, create key maps, modify the sound of the samples with synth parameters etc.
The main panel of the NN-XT can be folded like any other Reason Essentials device. Note that folding the main panel will also fold the remote editor regardless of its current state.