src/vs/workbench/contrib/debug/browser/callStackView.ts/CallStackDataSource/getThreadChildren
class CallStackDataSource:	private getThreadChildren(thread: Thread): Promise<CallStackItem[]> {
		return this.getThreadCallstack(thread).then(children => {
			// Check if some stack frames should be hidden under a parent element since they are deemphasized
			const result: CallStackItem[] = [];
			children.forEach((child, index) => {
				if (child instanceof StackFrame && child.source && isDeemphasized(child)) {
					// Check if the user clicked to show the deemphasized source
					if (this.deemphasizedStackFramesToShow.indexOf(child) === -1) {
						if (result.length) {
							const last = result[result.length - 1];
							if (last instanceof Array) {
								// Collect all the stackframes that will be "collapsed"
								last.push(child);
								return;
							}
						}

						const nextChild = index < children.length - 1 ? children[index + 1] : undefined;
						if (nextChild instanceof StackFrame && nextChild.source && isDeemphasized(nextChild)) {
							// Start collecting stackframes that will be "collapsed"
							result.push([child]);
							return;
						}
					}
				}

				result.push(child);
			});

			return result;
		});
	}