Add editor track traversal keys (Z-V)

osu.Game/Screens/Edit/Editor.cs

@@ -33,6 +33,7 @@
 using osu.Game.Resources.Localisation.Web;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Screens.Edit.Components;
 using osu.Game.Screens.Edit.Components.Menus;
 using osu.Game.Screens.Edit.Components.Timelines.Summary;
@@ -475,6 +476,44 @@ protected override bool OnKeyDown(KeyDownEvent e)
                 case Key.Right:
                     seek(e, 1);
                     return true;
+
+                // Track traversal keys.
+                // Matching osu-stable implementations.
+                case Key.Z:
+                    // Seek to first object time, or track start if already there.
+                    double? firstObjectTime = editorBeatmap.HitObjects.FirstOrDefault()?.StartTime;
+
+                    if (firstObjectTime == null || clock.CurrentTime == firstObjectTime)
+                        clock.Seek(0);
+                    else
+                        clock.Seek(firstObjectTime.Value);
+                    return true;
+
+                case Key.X:
+                    // Restart playback from beginning of track.
+                    clock.Seek(0);
+                    clock.Start();
+                    return true;
+
+                case Key.C:
+                    // Pause or resume.
+                    if (clock.IsRunning)
+                        clock.Stop();
+                    else
+                        clock.Start();
+                    return true;
+
+                case Key.V:
+                    // Seek to last object time, or track end if already there.
+                    // Note that in osu-stable subsequent presses when at track end won't return to last object.
+                    // This has intentionally been changed to make it more useful.
+                    double? lastObjectTime = editorBeatmap.HitObjects.LastOrDefault()?.GetEndTime();
+
+                    if (lastObjectTime == null || clock.CurrentTime == lastObjectTime)
+                        clock.Seek(clock.TrackLength);
+                    else
+                        clock.Seek(lastObjectTime.Value);
+                    return true;
             }
 
             return base.OnKeyDown(e);