src/vs/workbench/contrib/webview/browser/overlayWebview.ts/OverlayWebview/container
class OverlayWebview:	public get container(): HTMLElement {
		if (this._isDisposed) {
			throw new Error(`DynamicWebviewEditorOverlay has been disposed`);
		}

		if (!this._container) {
			this._container = document.createElement('div');
			this._container.id = `webview-${this.id}`;
			this._container.style.visibility = 'hidden';

			// Webviews cannot be reparented in the dom as it will destroy their contents.
			// Mount them to a high level node to avoid this.
			this._layoutService.container.appendChild(this._container);
		}

		return this._container;
	}