src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts/BackLayerWebView/clearInsets
class BackLayerWebView:	clearInsets() {
		if (this._disposed) {
			return;
		}

		this._sendMessageToWebview({
			type: 'clear'
		});

		this.insetMapping = new Map();
		this.reversedInsetMapping = new Map();
	}