src/vs/base/browser/ui/grid/gridview.ts/BranchNode/priority
class BranchNode:	get priority(): LayoutPriority {
		if (this.children.length === 0) {
			return LayoutPriority.Normal;
		}

		const priorities = this.children.map(c => typeof c.priority === 'undefined' ? LayoutPriority.Normal : c.priority);

		if (priorities.some(p => p === LayoutPriority.High)) {
			return LayoutPriority.High;
		} else if (priorities.some(p => p === LayoutPriority.Low)) {
			return LayoutPriority.Low;
		}

		return LayoutPriority.Normal;
	}