Events bubble down the frame stack until it finds a frame with a handler.

For example, this allows you to have an OnClick handler on a parent frame, and child frames who cover the parent frame, but the parent frame still receives the click events (unless the child subscribes to the event).

DepthsBelow/DepthsBelow/GUI/Frame.cs

@@ -138,6 +138,13 @@ namespace DepthsBelow.GUI
 		/// </summary>
 		public event OnClickHandler OnClick;
 		/// <summary>
+		/// Gets the number of subscribers to the <see cref="OnClickHandler" /> event.
+		/// </summary>
+		public int OnClickCount
+		{
+			get { return (OnClick != null) ? OnClick.GetInvocationList().Length : 0; }
+		}
+		/// <summary>
 		/// <see cref="OnClickHandler" /> event arguments.
 		/// </summary>
 		public class OnClickArgs : EventArgs

DepthsBelow/DepthsBelow/GUIManager.cs

@@ -29,14 +29,9 @@ namespace DepthsBelow
 		{
 			var clickRectangle = new Rectangle(position.X, position.Y, 1, 1);
 
-			var intersections = new List<Frame>();
-
-			foreach (var frame in Frames)
-			{
-				if (clickRectangle.Intersects(frame.AbsoluteRectangle))
-					intersections.Add(frame);
-			}
-
+			// Create a list of all frames which have an OnClick handler and intersects with the click position
+			var intersections = Frames.Where(frame => frame.OnClickCount > 0).Where(frame => clickRectangle.Intersects(frame.AbsoluteRectangle)).ToList();
+			// Get the topmost frame of that list
 			var topFrame = GetTopFrame(intersections);
 
 			if (topFrame != null)