src/vs/workbench/browser/parts/views/viewPaneContainer.ts/ViewPaneContainer/getOptimalWidth
class ViewPaneContainer:	getOptimalWidth(): number {
		const additionalMargin = 16;
		const optimalWidth = Math.max(...this.panes.map(view => view.getOptimalWidth() || 0));
		return optimalWidth + additionalMargin;
	}