diff --git a/OpenRA.Mods.RA/Player/ProductionQueue.cs b/OpenRA.Mods.RA/Player/ProductionQueue.cs
index 46fb2eb5d4..8a095f96ee 100644
--- a/OpenRA.Mods.RA/Player/ProductionQueue.cs
+++ b/OpenRA.Mods.RA/Player/ProductionQueue.cs
@@ -166,7 +166,7 @@ namespace OpenRA.Mods.RA
 			Produceable[self.World.Map.Rules.Actors[key]].Visible = false;
 		}
 
-		public void PrerequisitesItemVisable(string key)
+		public void PrerequisitesItemVisible(string key)
 		{
 			Produceable[self.World.Map.Rules.Actors[key]].Visible = true;
 		}
diff --git a/OpenRA.Mods.RA/Player/TechTree.cs b/OpenRA.Mods.RA/Player/TechTree.cs
index 131818239f..24e76c2a7a 100755
--- a/OpenRA.Mods.RA/Player/TechTree.cs
+++ b/OpenRA.Mods.RA/Player/TechTree.cs
@@ -142,7 +142,7 @@ namespace OpenRA.Mods.RA
 					watcher.PrerequisitesItemHidden(Key);
 
 				if (!nowHidden && hidden)
-					watcher.PrerequisitesItemVisable(Key);
+					watcher.PrerequisitesItemVisible(Key);
 
 				if (nowHasPrerequisites && !hasPrerequisites)
 					watcher.PrerequisitesAvailable(Key);
diff --git a/OpenRA.Mods.RA/SupportPowers/SupportPowerManager.cs b/OpenRA.Mods.RA/SupportPowers/SupportPowerManager.cs
index c0f9cacbc2..5bceff7b41 100644
--- a/OpenRA.Mods.RA/SupportPowers/SupportPowerManager.cs
+++ b/OpenRA.Mods.RA/SupportPowers/SupportPowerManager.cs
@@ -144,7 +144,7 @@ namespace OpenRA.Mods.RA
 		}
 
 		public void PrerequisitesItemHidden(string key) { }
-		public void PrerequisitesItemVisable(string key) { }
+		public void PrerequisitesItemVisible(string key) { }
 	}
 
 	public class SupportPowerInstance
diff --git a/OpenRA.Mods.RA/TraitsInterfaces.cs b/OpenRA.Mods.RA/TraitsInterfaces.cs
index 63c088db17..0e166c14ff 100755
--- a/OpenRA.Mods.RA/TraitsInterfaces.cs
+++ b/OpenRA.Mods.RA/TraitsInterfaces.cs
@@ -33,7 +33,7 @@ namespace OpenRA.Mods.RA
 		void PrerequisitesAvailable(string key);
 		void PrerequisitesUnavailable(string key);
 		void PrerequisitesItemHidden(string key);
-		void PrerequisitesItemVisable(string key);
+		void PrerequisitesItemVisible(string key);
 	}
 
 	public interface ITechTreePrerequisite