I’ve now found that the visibility setting only affects widgets. So a widget set to “Visible” will block interaction with other widgets behind it, but won’t prevent mouse input events from firing in the player controller for example.
So since UMG can’t automatically consume mouse clicks, is there some way to check if the mouse is over a specific widget?
This way, in the player’s mouse down event, before performing the line trace I could first check if any part of the hud widget is blocking the mouse.