src/vs/workbench/contrib/debug/browser/loadedScriptsView.ts/BaseTreeItem/oneChild
class BaseTreeItem:	private oneChild(): BaseTreeItem | undefined {
		if (!this._source && !this._showedMoreThanOne && this.skipOneChild()) {
			if (this._children.size === 1) {
				return this._children.values().next().value;
			}
			// if a node had more than one child once, it will never be skipped again
			if (this._children.size > 1) {
				this._showedMoreThanOne = true;
			}
		}
		return undefined;
	}