diff --git a/OpenRA.Mods.Mobius/Traits/Palettes/ColorPickerColorShift.cs b/OpenRA.Mods.Mobius/Traits/Palettes/ColorPickerColorShift.cs
index 519fa02..e675dfc 100644
--- a/OpenRA.Mods.Mobius/Traits/Palettes/ColorPickerColorShift.cs
+++ b/OpenRA.Mods.Mobius/Traits/Palettes/ColorPickerColorShift.cs
@@ -18,7 +18,7 @@ namespace OpenRA.Mods.Mobius.Traits
 {
 	[TraitLocation(SystemActors.World | SystemActors.EditorWorld)]
 	[Desc("Create a color picker palette from another palette.")]
-	class ColorPickerColorShiftInfo : TraitInfo
+	sealed class ColorPickerColorShiftInfo : TraitInfo
 	{
 		[PaletteReference]
 		[FieldLoader.Require]
@@ -43,7 +43,7 @@ class ColorPickerColorShiftInfo : TraitInfo
 		public override object Create(ActorInitializer init) { return new ColorPickerColorShift(this); }
 	}
 
-	class ColorPickerColorShift : ILoadsPalettes, ITickRender
+	sealed class ColorPickerColorShift : ILoadsPalettes, ITickRender
 	{
 		readonly ColorPickerColorShiftInfo info;
 		Color color;
diff --git a/OpenRA.Mods.Mobius/UtilityCommands/RemasterCheckMissingSprites.cs b/OpenRA.Mods.Mobius/UtilityCommands/RemasterCheckMissingSprites.cs
index 20f163b..397d9b8 100644
--- a/OpenRA.Mods.Mobius/UtilityCommands/RemasterCheckMissingSprites.cs
+++ b/OpenRA.Mods.Mobius/UtilityCommands/RemasterCheckMissingSprites.cs
@@ -16,7 +16,7 @@
 
 namespace OpenRA.Mods.Mobius.UtilityCommands
 {
-	class RemasterCheckMissingSprites : IUtilityCommand
+	sealed class RemasterCheckMissingSprites : IUtilityCommand
 	{
 		string IUtilityCommand.Name => "--remaster-check-missing-sprites";
 
diff --git a/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpSequenceSheetsCommand.cs b/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpSequenceSheetsCommand.cs
index 22b62f3..ece2b52 100644
--- a/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpSequenceSheetsCommand.cs
+++ b/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpSequenceSheetsCommand.cs
@@ -15,7 +15,7 @@
 
 namespace OpenRA.Mods.Mobius.UtilityCommands
 {
-	class DumpSequenceSheetsCommand : IUtilityCommand
+	sealed class DumpSequenceSheetsCommand : IUtilityCommand
 	{
 		static readonly int[] ChannelMasks = { 2, 1, 0, 3 };
 
diff --git a/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpTilesetSheetsCommand.cs b/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpTilesetSheetsCommand.cs
index c8132e4..e0d5193 100644
--- a/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpTilesetSheetsCommand.cs
+++ b/OpenRA.Mods.Mobius/UtilityCommands/RemasterDumpTilesetSheetsCommand.cs
@@ -15,7 +15,7 @@
 
 namespace OpenRA.Mods.Mobius.UtilityCommands
 {
-	class DumpTilesetSheetsCommand : IUtilityCommand
+	sealed class DumpTilesetSheetsCommand : IUtilityCommand
 	{
 		static readonly int[] ChannelMasks = { 2, 1, 0, 3 };
 
diff --git a/OpenRA.Mods.Mobius/UtilityCommands/RemasterTilesetConverter.cs b/OpenRA.Mods.Mobius/UtilityCommands/RemasterTilesetConverter.cs
index 15f3f13..ad16762 100644
--- a/OpenRA.Mods.Mobius/UtilityCommands/RemasterTilesetConverter.cs
+++ b/OpenRA.Mods.Mobius/UtilityCommands/RemasterTilesetConverter.cs
@@ -19,7 +19,7 @@
 
 namespace OpenRA.Mods.Mobius.UtilityCommands
 {
-	class RemasterTilesetConverter : IUtilityCommand
+	sealed class RemasterTilesetConverter : IUtilityCommand
 	{
 		string IUtilityCommand.Name { get { return "--convert-tileset"; } }