Percussion part has two instruments, but three playback lanes

I am having trouble understanding how to get percussion parts to sound and be notated correctly. I have created a percussion kit and map with only two instruments on two lines: Bass Drum (Dagu, a Chinese bass drum) and tam-tam. Although, in the Setup window I appear to have created the one player playing those two instruments, when I go to the Play interface there are three instruments: Percussion, which is the “name” of the part, which, itself, will not ‘play’ any VST instrument – and yet it is assigned a VST there and when I add notes in piano roll, those notes get added to BOTH of the instruments I defined in the percussion kit – and the two defined instruments in the percussion map. I have assigned the two actual instruments to play on two separate channels of a Kontakt VST and assigned the audio out for each instruments to a different audio output. Please see the video I made at this link: Dropbox Capture

At the moment, the new Key Editor is lacking the dedicated percussion editor that was present in previous versions of Dorico. It will be making a return as soon as possible.

In the meantime, you are advised to input your material into each of the component instruments in the percussion kit rather than into the kit’s own instrument (which would not normally receive notes directly, instead showing notes that it automatically condenses from the constituent instruments in the kit).