I highly suggest that the sub quests part of black box objectives remain in the quest HUD or quest listing in the menu while you are doing the missions until the quest objective is complete. I am now in Rot in the Slums, and multiple cool objectives were available BUT because I was using my raven all of the items vanished in favor of ONLY the Assassinate text remains because my bird caught sight of the Bishop. I no longer know where I could have gone with the black box. I now have to go find a video of the various options, which means I'm not playing the game, I'm watching it.
QOL needed. Black Box missions are to be treated as much more worthy than basic vanilla, and consequently need a QOL upgrade so we see all the options until the quest completes entirely. Whether that means it remains in the HUD or just in the Quest log, we and the black box missions deserve it.