update player list in lobby gracefully for better user experience

OpenRA.Game/Widgets/GridLayout.cs

@@ -41,6 +41,11 @@ namespace OpenRA.Widgets
 
 			widget.ContentHeight = Math.Max(widget.ContentHeight, pos.Y + widget.ItemSpacing + w.Bounds.Height);
 		}
+
+		public void AdjustChildren()
+		{
+
+		}
 	}
 }
 

OpenRA.Game/Widgets/ListLayout.cs

@@ -24,5 +24,16 @@ namespace OpenRA.Widgets
 			w.Bounds.Y += widget.ContentHeight;
 			widget.ContentHeight += w.Bounds.Height + widget.ItemSpacing;
 		}
+
+
+		public void AdjustChildren()
+		{
+			widget.ContentHeight = widget.ItemSpacing;
+			foreach (var w in widget.Children)
+			{
+				w.Bounds.Y = widget.ContentHeight;
+				widget.ContentHeight += w.Bounds.Height + widget.ItemSpacing;
+			}
+		}
 	}
 }

OpenRA.Game/Widgets/ScrollPanelWidget.cs

@@ -14,7 +14,7 @@ using OpenRA.Graphics;
 
 namespace OpenRA.Widgets
 {
-	public interface ILayout { void AdjustChild(Widget w); }
+	public interface ILayout { void AdjustChild(Widget w); void AdjustChildren(); }
 
 	public class ScrollPanelWidget : Widget
 	{
@@ -95,6 +95,8 @@ namespace OpenRA.Widgets
 
 			Game.Renderer.EnableScissor(backgroundRect.X + 1, backgroundRect.Y + 1, backgroundRect.Width - 2, backgroundRect.Height - 2);
 
+			Layout.AdjustChildren();
+
 			foreach (var child in Children)
 				child.DrawOuter();