src/vs/editor/contrib/peekView/peekView.ts/PeekViewWidget/_fillContainer
class PeekViewWidget:	protected _fillContainer(container: HTMLElement): void {
		this.setCssClass('peekview-widget');

		this._headElement = dom.$<HTMLDivElement>('.head');
		this._bodyElement = dom.$<HTMLDivElement>('.body');

		this._fillHead(this._headElement);
		this._fillBody(this._bodyElement);

		container.appendChild(this._headElement);
		container.appendChild(this._bodyElement);
	}