Interface improvement for area fire

[Anton]

Thank you for the explanation, Mobhack. That code quirk is indeed a bug that had to be fixed, but the current solution has the negative side effect of the general inconvenience of Z-fire, including situations where one is not abusing it, for example—firing from MMG through smoke at an enemy unit visible by other friendly units.

I wish you would fix it without introducing an artificial inconvenience into the interface. The correct fix would be simply to exclude from the bombardment screen artillery units that have Z-fired, as you already do those that have direct-fired or moved.