private void StartRecordTilesetChanges() { // Copy the selected tileset's original settings to our local backup Tileset tileset = this.SelectedTileset.Res; if (tileset != null) { if (this.tilesetBackup == null) { this.tilesetBackup = new Tileset(); } tileset.CopyTo(this.tilesetBackup); this.backupTarget = this.SelectedTileset; } else { this.backupTarget = null; } }