thanks for the clarification
I did an "alpha strike" to make all my creatures attack, and as soon as all my creatures got the attack icon, an error message appeared

noticed on the screenshot , in the prompt " selecting creatures to attack null "
- NullPointerException | Open
- Code: Select all
Forge Version: 1.5.13-r${forge.revision}${forge.specialStatus} (mixed revisions detected; please update from the root directory)
Operating System: Windows XP 5.1 x86
Java Version: 1.7.0_10 Oracle Corporation
java.lang.NullPointerException
at forge.gui.player.HumanPlay.payCostDuringAbilityResolve(HumanPlay.java:630)
at forge.gui.player.PlayerControllerHuman.payManaOptional(PlayerControllerHuman.java:716)
at forge.game.combat.CombatUtil.checkPropagandaEffects(CombatUtil.java:990)
at forge.game.phase.PhaseHandler.declareAttackersTurnBasedAction(PhaseHandler.java:473)
at forge.game.phase.PhaseHandler.onPhaseBegin(PhaseHandler.java:281)
at forge.game.phase.PhaseHandler.startFirstTurn(PhaseHandler.java:999)
at forge.game.GameAction.startGame(GameAction.java:1503)
at forge.game.Match.startGame(Match.java:80)
at forge.control.FControl$4.run(FControl.java:437)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
unfortunately the match was dead following that error, as the Ok on the prompt wasn't responsive anymore, and neither click on the creature to turn them off attacking was doing anything