Variables are collapsed when the full Call Stack is displayed

For large applications the full call stack may take some time to display. During this time the user may start drilling into the current variables. When the entire call stack is eventually displayed, the expanded variables are collapsed, causing the user to lose their place. This can be quite frustrating.

首先使用大型应用复现该问题：在完整调用栈加载期间展开变量，然后观察加载完成后变量是否会折叠。跟踪 DevTools 中调用栈刷新和变量树状态处理的过程。当完整调用栈显示后，展开的变量仍能保留其状态，即表示完成。

由索引模型根据 Issue 内容生成。