When [Bug Report] tree-table is lazily loaded, only the first-tier nodes will have the loading effect, and their descendants will not have the loading effect.

[zhixiaotong]

Element UI version

2.9.1

OS/Browsers version

Chrome 66.0.3359.139

Vue version

2.6.10

Reproduction Link

https://codepen.io/zhixiaotong/pen/PvxQBP

Steps to reproduce

点击展开子节点即可重现

What is Expected?

不同层级都可以正常显示loading效果

What is actually happening?

只有跟层级的节点可以显示

[element-bot]

Translation of this issue:

Element UI version

2.9.1

OS/Browsers version

Chrome 66.0.3359.139

Vue version

2.6.10

Reproduction Link

Https://codepen.io/zhixiaotong/pen/PvxQBP

Steps to reproduce

Reproduce by clicking on the expanded child node

What is Expected?

Loading effect can be displayed at different levels

What is actually happening?

Only hierarchical nodes can be displayed