check palette references

OpenRA.Mods.Common/Traits/World/PaletteFromRGBA.cs

@@ -18,19 +18,25 @@ namespace OpenRA.Mods.Common.Traits
 	[Desc("Creates a single color palette without any base palette file.")]
 	class PaletteFromRGBAInfo : ITraitInfo
 	{
-		[FieldLoader.Require]
+		[FieldLoader.Require, PaletteDefinition]
 		[Desc("internal palette name")]
 		public readonly string Name = null;
+
 		[Desc("If defined, load the palette only for this tileset.")]
 		public readonly string Tileset = null;
+
 		[Desc("red color component")]
 		public readonly int R = 0;
+
 		[Desc("green color component")]
 		public readonly int G = 0;
+
 		[Desc("blue color component")]
 		public readonly int B = 0;
+
 		[Desc("alpha channel (transparency)")]
 		public readonly int A = 255;
+
 		public readonly bool AllowModifiers = true;
 
 		public object Create(ActorInitializer init) { return new PaletteFromRGBA(init.World, this); }