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

DeleteCardButton.cs

@@ -0,0 +1,19 @@
+using Godot;
+using System;
+
+public partial class DeleteCardButton : Button
+{
+	// Called when the node enters the scene tree for the first time.
+	public override void _Ready()
+	{
+	}
+
+	// Called every frame. 'delta' is the elapsed time since the previous frame.
+	public override void _Process(double delta)
+	{
+	}
+	private void EnableToggled(bool newState)
+	{
+		Disabled = !newState;
+	}
+}