'Insert row above' while using nestedRows produces Uncaught error when we use it for a first child [Urgent]

[AMBudnik]

Description

'Insert row above' while using nestedRows produces Uncaught error when we use it for a first child.

We have fixed the behavior of using 'Insert row above' but it apparently did not cover this case. If you try to use this option on any other element (parent, nth-child) it works as expected.

Steps to reproduce

1. Use 'Insert row above' on the Alabama Shakes (2nd row)

Result
The row is not added and you get the console error.

Demo

https://jsfiddle.net/zo1jhx49/ 7.4.2 (broken)
https://jsfiddle.net/vf4nxou7/ 8.0.0-beta1 (broken)
https://jsfiddle.net/mpdw5t78/ 8.0.0-beta2-rev22 (broken)
https://jsfiddle.net/0bfsrLqp/4/ 8.0.0-rev1 (broken)
https://jsfiddle.net/AMBudnik/08vwazpf/ 8.0.0 (broken)

Your environment

• Handsontable version: 7.4.2
• Browser Name and version: Chrome 83
• Operating System: macOS Catalina 10.15.3

Inform Zen 26480

[AMBudnik]

This issue is closed temporarily. It will be reopened for development as it became a part of Interoperability problems between Nested Rows and some core features task reported at #7510

I will make sure to inform everyone interested in this topic after the official fix.

Please feel welcome to makes any comments on this issue. And if you experience similar behavior feel free to contact me at support@handsontable.com