src/vs/editor/contrib/wordHighlighter/wordHighlighter.ts/WordHighlighterContribution/constructor
class WordHighlighterContribution:	constructor(editor: ICodeEditor, @IContextKeyService contextKeyService: IContextKeyService) {
		super();
		this.wordHighlighter = null;
		const createWordHighlighterIfPossible = () => {
			if (editor.hasModel()) {
				this.wordHighlighter = new WordHighlighter(editor, contextKeyService);
			}
		};
		this._register(editor.onDidChangeModel((e) => {
			if (this.wordHighlighter) {
				this.wordHighlighter.dispose();
				this.wordHighlighter = null;
			}
			createWordHighlighterIfPossible();
		}));
		createWordHighlighterIfPossible();
	}