fix: Fix the instrumental selector still allowing inputs after a song is selected

source/funkin/ui/freeplay/CapsuleOptionsMenu.hx

@@ -22,6 +22,8 @@ class CapsuleOptionsMenu extends FlxSpriteGroup
 
   var currentInstrumental:FlxText;
 
+  var busy:Bool = false;
+
   public function new(parent:FreeplayState, x:Float = 0, y:Float = 0, instIds:Array<String>):Void
   {
     super(x, y);
@@ -66,24 +68,34 @@ class CapsuleOptionsMenu extends FlxSpriteGroup
       destroy();
       return;
     }
-    @:privateAccess
-    if (parent.controls.BACK)
+    var changedInst = false;
+
+    if (!busy)
     {
-      close();
-      return;
+      @:privateAccess
+      if (parent.controls.BACK)
+      {
+        close();
+        return;
+      }
+
+      if (parent.getControls().UI_LEFT_P)
+      {
+        currentInstrumentalIndex = (currentInstrumentalIndex + 1) % instrumentalIds.length;
+        changedInst = true;
+      }
+      if (parent.getControls().UI_RIGHT_P)
+      {
+        currentInstrumentalIndex = (currentInstrumentalIndex - 1 + instrumentalIds.length) % instrumentalIds.length;
+        changedInst = true;
+      }
+      if (parent.getControls().ACCEPT)
+      {
+        busy = true;
+        onConfirm(instrumentalIds[currentInstrumentalIndex] ?? '');
+      }
     }
 
-    var changedInst = false;
-    if (parent.getControls().UI_LEFT_P)
-    {
-      currentInstrumentalIndex = (currentInstrumentalIndex + 1) % instrumentalIds.length;
-      changedInst = true;
-    }
-    if (parent.getControls().UI_RIGHT_P)
-    {
-      currentInstrumentalIndex = (currentInstrumentalIndex - 1 + instrumentalIds.length) % instrumentalIds.length;
-      changedInst = true;
-    }
     if (!changedInst && currentInstrumental.text == '') changedInst = true;
 
     if (changedInst)
@@ -91,11 +103,6 @@ class CapsuleOptionsMenu extends FlxSpriteGroup
       currentInstrumental.text = instrumentalIds[currentInstrumentalIndex].toTitleCase() ?? '';
       if (currentInstrumental.text == '') currentInstrumental.text = 'Default';
     }
-
-    if (parent.getControls().ACCEPT)
-    {
-      onConfirm(instrumentalIds[currentInstrumentalIndex] ?? '');
-    }
   }
 
   public function close():Void