src/vs/workbench/browser/parts/views/treeView.ts/Aligner/alignIconWithTwisty
class Aligner:	public alignIconWithTwisty(treeItem: ITreeItem): boolean {
		if (treeItem.collapsibleState !== TreeItemCollapsibleState.None) {
			return false;
		}
		if (!this.hasIcon(treeItem)) {
			return false;
		}

		if (this._tree) {
			const parent: ITreeItem = this._tree.getParentElement(treeItem) || this._tree.getInput();
			if (this.hasIcon(parent)) {
				return !!parent.children && parent.children.some(c => c.collapsibleState !== TreeItemCollapsibleState.None && !this.hasIcon(c));
			}
			return !!parent.children && parent.children.every(c => c.collapsibleState === TreeItemCollapsibleState.None || !this.hasIcon(c));
		} else {
			return false;
		}
	}