The Virtual Scouting tools appear black in scenes using real-world physical lighting values due to their UI Material Domain since they do not have an emissive channel and do not accommodate viewport exposure settings.
All the UI menus/icons/drawing tools appear as black (i.e. super under-exposed). Hunted it down to the exposure settings (real-world sun value = -14+ exposure compensation in viewport = materials are so dark they appear black).
In the master material for the VP Scouting Tools, its set to Translucent blend mode and since it is UI material no Emissive channel... switched to Surface material type and some usability progress (though just a start). The icons and drawing tools are still black.
Wondering if this is scratching on the surface of a larger bug of UI Material Domain materials that are used on meshes within a scene not accommodating for viewport/camera exposure settings.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-127964 in the post.