src/vs/workbench/contrib/markers/browser/markersTreeViewer.ts/VirtualDelegate/getHeight
class VirtualDelegate:	getHeight(element: MarkerElement): number {
		if (element instanceof Marker) {
			const viewModel = this.markersViewState.getViewModel(element);
			const noOfLines = !viewModel || viewModel.multiline ? element.lines.length : 1;
			return noOfLines * VirtualDelegate.LINE_HEIGHT;
		}
		return VirtualDelegate.LINE_HEIGHT;
	}