The interactivity problem has been solved. When creating my HUD, I specified its Z-order in the viewport to be higher than the Z-order of my draggable menu widget. This meant that it was ‘in the way’ of the menu item’s ability to receive hit tests.
However, I still don’t know why my draggable menu item won’t produce a visual, even though I hooked up its “default drag visual” in the create Drag and Drop operation node to a reference of itself, like Wes shows us in the training video.
If anyone could care to answer why that may be the case, that’d be great.