Make dragbox stateful to fix blueprint movement

osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs

@@ -152,15 +152,16 @@ protected override bool OnDragStart(DragStartEvent e)
             if (e.Button == MouseButton.Right)
                 return false;
 
-            if (!beginSelectionMovement())
-            {
-                if (!DragBox.UpdateDrag(e))
-                    return false;
+            if (beginSelectionMovement())
+                return true;
 
-                DragBox.FadeIn(250, Easing.OutQuint);
+            if (DragBox.HandleDrag(e))
+            {
+                DragBox.Show();
+                return true;
             }
 
-            return true;
+            return false;
         }
 
         protected override bool OnDrag(DragEvent e)
@@ -168,13 +169,10 @@ protected override bool OnDrag(DragEvent e)
             if (e.Button == MouseButton.Right)
                 return false;
 
-            if (!moveCurrentSelection(e))
-            {
-                if (!DragBox.UpdateDrag(e))
-                    return false;
-            }
+            if (DragBox.State == Visibility.Visible)
+                return DragBox.HandleDrag(e);
 
-            return true;
+            return moveCurrentSelection(e);
         }
 
         protected override bool OnDragEnd(DragEndEvent e)
@@ -182,13 +180,14 @@ protected override bool OnDragEnd(DragEndEvent e)
             if (e.Button == MouseButton.Right)
                 return false;
 
-            if (!finishSelectionMovement())
+            if (DragBox.State == Visibility.Visible)
             {
-                DragBox.FadeOut(250, Easing.OutQuint);
+                DragBox.Hide();
                 selectionHandler.UpdateVisibility();
+                return true;
             }
 
-            return true;
+            return finishSelectionMovement();
         }
 
         protected override bool OnKeyDown(KeyDownEvent e)

osu.Game/Screens/Edit/Compose/Components/DragBox.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using osu.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -15,7 +16,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
     /// <summary>
     /// A box that displays the drag selection and provides selection events for users to handle.
     /// </summary>
-    public class DragBox : CompositeDrawable
+    public class DragBox : CompositeDrawable, IStateful<Visibility>
     {
         protected readonly Action<RectangleF> PerformSelection;
 
@@ -57,7 +58,7 @@ private void load()
         /// </summary>
         /// <param name="e">The mouse event.</param>
         /// <returns>Whether the event should be handled and blocking.</returns>
-        public virtual bool UpdateDrag(MouseButtonEvent e)
+        public virtual bool HandleDrag(MouseButtonEvent e)
         {
             var dragPosition = e.ScreenSpaceMousePosition;
             var dragStartPosition = e.ScreenSpaceMouseDownPosition;
@@ -76,5 +77,26 @@ public virtual bool UpdateDrag(MouseButtonEvent e)
             PerformSelection?.Invoke(dragRectangle);
             return true;
         }
+
+        private Visibility state;
+
+        public Visibility State
+        {
+            get => state;
+            set
+            {
+                if (value == state) return;
+
+                state = value;
+                this.FadeTo(state == Visibility.Hidden ? 0 : 1, 250, Easing.OutQuint);
+                StateChanged?.Invoke(state);
+            }
+        }
+
+        public override void Hide() => State = Visibility.Hidden;
+
+        public override void Show() => State = Visibility.Visible;
+
+        public event Action<Visibility> StateChanged;
     }
 }

osu.Game/Screens/Edit/Compose/Components/Timeline/TimelineHitObjectDisplay.cs

@@ -52,6 +52,12 @@ protected override bool OnDrag(DragEvent e)
             return base.OnDrag(e);
         }
 
+        protected override bool OnDragEnd(DragEndEvent e)
+        {
+            lastDragEvent = null;
+            return base.OnDragEnd(e);
+        }
+
         protected override void Update()
         {
             // trigger every frame so drags continue to update selection while playback is scrolling the timeline.
@@ -81,7 +87,7 @@ public TimelineDragBox(Action<RectangleF> performSelect)
                 Alpha = 0.3f
             };
 
-            public override bool UpdateDrag(MouseButtonEvent e)
+            public override bool HandleDrag(MouseButtonEvent e)
             {
                 // store the original position of the mouse down, as we may be scrolled during selection.
                 if (lastMouseDown != e.ScreenSpaceMouseDownPosition)