Fix compose mode not showing distance snap grid when entering with a selection

osu.Game.Rulesets.Osu/Edit/OsuHitObjectComposer.cs

@@ -54,6 +54,9 @@ private void load()
             EditorBeatmap.SelectedHitObjects.CollectionChanged += (_, __) => updateDistanceSnapGrid();
             EditorBeatmap.PlacementObject.ValueChanged += _ => updateDistanceSnapGrid();
             distanceSnapToggle.ValueChanged += _ => updateDistanceSnapGrid();
+
+            // we may be entering the screen with a selection already active
+            updateDistanceSnapGrid();
         }
 
         protected override ComposeBlueprintContainer CreateBlueprintContainer(IEnumerable<DrawableHitObject> hitObjects)