render() {
    return (
      <div className="TexEditor-container">
        <div className="TeXEditor-root">
          <div className="TeXEditor-editor" onClick={this._focus}>
            <Editor
              blockRendererFn={this._blockRenderer}
              editorState={this.state.editorState}
              handleKeyCommand={this._handleKeyCommand}
              onChange={this._onChange}
              placeholder="Start a document..."
              readOnly={this.state.liveTeXEdits.count()}
              ref="editor"
              spellCheck={true}
            />
          </div>
        </div>
        <button onClick={this._insertTeX} className="TeXEditor-insert">
          {'Insert new TeX'}
        </button>
      </div>
    );
  }
While editing TeX, set the Draft editor to read-only. This allows us to
have a textarea within the DOM.