The issue was present in build 108 and still in build 187. While Boris FX's themselves work OK in the adjustment events (both in version 108 and 187), what is annoying (and unworkable) is that the Boris FX Editor (launched via the fx editor tab inside the Boris effect plugin) previews all black presets and a main black viewer window, so you are unable to see what the effects do (or select a preset) on your source video.
As a sidenote, the Boris FX Editor does work on adjustment tracks ...