tested version with most of the final functionality. Still a few known issues, like dragging to a row that extends to multiple lines

CommandHandler.cs

@@ -34,6 +34,8 @@ public partial class CommandHandler : Node
 	// Called when the node enters the scene tree for the first time.
 	public override void _Ready()
 	{
+		//force initialization of Deferer in main thread
+		_ = Deferer;
 		Settings = GetNode<Settings>("/root/Settings");
 		Game = GetNode<game>("/root/Game");
 		GetNode<TwitchChatWatcher>("/root/TwitchChatWatcher").IncomingCommand
@@ -51,6 +53,7 @@ public partial class CommandHandler : Node
 
 	private void IncomingCommand(Command command)
 	{
+		GD.Print(command.GetArgs().Remaining());
 		if (!Settings.IsUserAuthorized(command.User, command.IsStreamer,
 			command.IsModerator))
 			return;
@@ -167,7 +170,6 @@ public partial class CommandHandler : Node
 		var rowId = args.Pop();
 		var colorStr = args.Pop();
 		var color = Color.FromString(colorStr, new Color(0, 0, 0, 0));
-		GD.Print($"Recoloring row to {color}");
 		if (color.IsEqualApprox(new Color(0, 0, 0, 0)))
 			throw new Exception($"invalid color {colorStr}");
 		Game.RecolorRow(rowId, color);
@@ -195,7 +197,6 @@ public partial class CommandHandler : Node
 				_ => throw new Exception($"Unrecognized {nameof(StretchMode)}"),
 			};
 		}
-		GD.Print($"Stretch mode: {mode}");
 		var uri = new Uri(url);
 		GD.Print("Starting image download");
 		var resp = await Client.GetAsync(uri);