diff --git a/OpenRA.Game/Graphics/Minimap.cs b/OpenRA.Game/Graphics/Minimap.cs
index a20247c541..d146541c6b 100644
--- a/OpenRA.Game/Graphics/Minimap.cs
+++ b/OpenRA.Game/Graphics/Minimap.cs
@@ -122,7 +122,7 @@ namespace OpenRA.Graphics
 				
 				foreach (var t in world.Queries.WithTraitMultiple<IRadarSignature>())
 				{
-					if (!t.Actor.IsVisible())
+					if (!t.Actor.IsVisible(world.LocalPlayer))
 						continue;
 					
 					var color = t.Trait.RadarSignatureColor(t.Actor);
diff --git a/OpenRA.Game/Traits/TraitsInterfaces.cs b/OpenRA.Game/Traits/TraitsInterfaces.cs
index ca19fc01d7..833aa255fb 100644
--- a/OpenRA.Game/Traits/TraitsInterfaces.cs
+++ b/OpenRA.Game/Traits/TraitsInterfaces.cs
@@ -58,7 +58,7 @@ namespace OpenRA.Traits
 		Color RadarSignatureColor(Actor self);
 	}
 	
-	public interface IVisibilityModifier { bool IsVisible(Actor self); }
+	public interface IVisibilityModifier { bool IsVisible(Actor self, Player byPlayer); }
 	public interface IRadarColorModifier { Color RadarColorOverride(Actor self); }
 	public interface IOccupySpace
 	{
diff --git a/OpenRA.Game/Widgets/WorldInteractionControllerWidget.cs b/OpenRA.Game/Widgets/WorldInteractionControllerWidget.cs
index 7f15a0e553..2bbdebe7f5 100644
--- a/OpenRA.Game/Widgets/WorldInteractionControllerWidget.cs
+++ b/OpenRA.Game/Widgets/WorldInteractionControllerWidget.cs
@@ -174,7 +174,7 @@ namespace OpenRA.Widgets
 		IEnumerable<Actor> SelectActorsInBox(World world, float2 a, float2 b)
 		{
 			return world.FindUnits(a, b)
-				.Where( x => x.HasTrait<Selectable>() && x.IsVisible() )
+				.Where( x => x.HasTrait<Selectable>() && x.IsVisible(world.LocalPlayer) )
 				.GroupBy(x => (x.Owner == world.LocalPlayer) ? x.Info.Traits.Get<SelectableInfo>().Priority : 0)
 				.OrderByDescending(g => g.Key)
 				.Select( g => g.AsEnumerable() )
diff --git a/OpenRA.Game/Widgets/WorldTooltipWidget.cs b/OpenRA.Game/Widgets/WorldTooltipWidget.cs
index f1a6bc535b..ccf6353dc3 100644
--- a/OpenRA.Game/Widgets/WorldTooltipWidget.cs
+++ b/OpenRA.Game/Widgets/WorldTooltipWidget.cs
@@ -44,7 +44,7 @@ namespace OpenRA.Widgets
 			}
 			
 			var actor = world.FindUnitsAtMouse(Viewport.LastMousePos).FirstOrDefault();
-			if (actor == null || !actor.IsVisible())
+			if (actor == null || !actor.IsVisible(world.LocalPlayer))
 				return;
 		
 			var text = actor.Info.Traits.Contains<ValuedInfo>()
diff --git a/OpenRA.Game/WorldUtils.cs b/OpenRA.Game/WorldUtils.cs
index 3c7db25eec..1cfc018262 100755
--- a/OpenRA.Game/WorldUtils.cs
+++ b/OpenRA.Game/WorldUtils.cs
@@ -40,7 +40,7 @@ namespace OpenRA
 		public static IEnumerable<Actor> FindUnitsAtMouse(this World world, int2 mouseLocation)
 		{
 			var loc = mouseLocation + Game.viewport.Location;
-			return FindUnits(world, loc, loc).Where(a => a.IsVisible());
+			return FindUnits(world, loc, loc).Where(a => a.IsVisible(world.LocalPlayer));
 		}
 
 		public static IEnumerable<Actor> FindUnits(this World world, float2 a, float2 b)
@@ -101,7 +101,7 @@ namespace OpenRA
 					world.IsCellBuildable(t, building.WaterBound, toIgnore));
 		}
 
-		public static bool IsVisible(this Actor a)			/* must never be relied on in synced code! */
+		public static bool IsVisible(this Actor a, Player byPlayer)			/* must never be relied on in synced code! */
 		{
 			if (a.World.LocalPlayer != null && a.World.LocalPlayer.Shroud.Disabled)
 				return true;
@@ -110,7 +110,7 @@ namespace OpenRA
 			if (!Shroud.GetVisOrigins(a).Any(o => a.World.Map.IsInMap(o) && shroud.exploredCells[o.X, o.Y]))		// covered by shroud
 				return false;
 
-			if (a.TraitsImplementing<IVisibilityModifier>().Any(t => !t.IsVisible(a)))
+			if (a.TraitsImplementing<IVisibilityModifier>().Any(t => !t.IsVisible(a, byPlayer)))
 				return false;
 
 			return true;
diff --git a/OpenRA.Mods.RA/InvisibleToOthers.cs b/OpenRA.Mods.RA/InvisibleToOthers.cs
index b2895bdbd5..b1ccf2273a 100644
--- a/OpenRA.Mods.RA/InvisibleToOthers.cs
+++ b/OpenRA.Mods.RA/InvisibleToOthers.cs
@@ -18,9 +18,9 @@ namespace OpenRA.Mods.RA
 
 	class InvisibleToOthers : IRenderModifier, IVisibilityModifier, IRadarColorModifier
 	{
-		public bool IsVisible(Actor self)
+		public bool IsVisible(Actor self, Player byPlayer)
 		{
-			return self.Owner == self.World.LocalPlayer;
+			return self.Owner == byPlayer;
 		}
 		
 		public Color RadarColorOverride(Actor self)
diff --git a/OpenRA.Mods.RA/Modifiers/FrozenUnderFog.cs b/OpenRA.Mods.RA/Modifiers/FrozenUnderFog.cs
index c74bce105f..026eee64da 100644
--- a/OpenRA.Mods.RA/Modifiers/FrozenUnderFog.cs
+++ b/OpenRA.Mods.RA/Modifiers/FrozenUnderFog.cs
@@ -29,17 +29,17 @@ namespace OpenRA.Mods.RA
 			shroud = self.World.WorldActor.Trait<Shroud>();
 		}
 
-		public bool IsVisible(Actor self)
+		public bool IsVisible(Actor self, Player byPlayer)
 		{
 			return self.World.LocalPlayer == null
-				|| self.Owner == self.World.LocalPlayer
+				|| self.Owner == byPlayer
 				|| self.World.LocalPlayer.Shroud.Disabled
 				|| Shroud.GetVisOrigins(self).Any(o => self.World.Map.IsInMap(o) && shroud.visibleCells[o.X, o.Y] != 0);
 		}
 
 		public IEnumerable<Renderable> ModifyRender(Actor self, IEnumerable<Renderable> r)
 		{
-			if (IsVisible(self))
+			if (IsVisible(self, self.World.LocalPlayer))
 				cache = r.ToArray();
 
 			return cache;
diff --git a/OpenRA.Mods.RA/Modifiers/HiddenUnderFog.cs b/OpenRA.Mods.RA/Modifiers/HiddenUnderFog.cs
index e99f929a91..f43751d565 100644
--- a/OpenRA.Mods.RA/Modifiers/HiddenUnderFog.cs
+++ b/OpenRA.Mods.RA/Modifiers/HiddenUnderFog.cs
@@ -27,10 +27,10 @@ namespace OpenRA.Mods.RA
 			shroud = self.World.WorldActor.Trait<Shroud>();
 		}
 
-		public bool IsVisible(Actor self)
+		public bool IsVisible(Actor self, Player byPlayer)
 		{
 			return self.World.LocalPlayer == null
-				|| self.Owner == self.World.LocalPlayer
+				|| self.Owner == byPlayer
 				|| self.World.LocalPlayer.Shroud.Disabled
 				|| shroud.visibleCells[self.Location.X, self.Location.Y] > 0;
 		}
@@ -38,7 +38,7 @@ namespace OpenRA.Mods.RA
 		static Renderable[] Nothing = { };
 		public IEnumerable<Renderable> ModifyRender(Actor self, IEnumerable<Renderable> r)
 		{
-			return IsVisible(self) ? r : Nothing;
+			return IsVisible(self, self.World.LocalPlayer) ? r : Nothing;
 		}
 	}
 }