DataTable scrollHeight doesn't calculate correctly with frozen columns and header groups

[PaulInglis]

There is no guarantee in receiving an immediate response in GitHub Issue Tracker, If you'd like to secure our response, you may consider PrimeReact PRO Support where support is provided within 4 business hours

I'm submitting a ... (check one with "x")

[X] bug report
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://forum.primefaces.org/viewforum.php?f=57

Codesandbox Case (Bug Reports)
Please fork the codesandbox below and create a case demonstrating your bug report. Issues without a codesandbox have much less possibility to be reviewed.

It's a convoluted example, but this is essentially what we have in our project. A table with the first 2 columns fixed and header groups to highlight different areas of the report table
https://codesandbox.io/s/primereact-test-vzsde

Current behavior

When viewing a table with frozen columns and header groups the frozen table gets calculated to one height and the unfrozen part to a completely different height.

Expected behavior

Both sides of the table should be the same height regardless of percentage or fixed height or whether they are frozen or have colum header grops.

Minimal reproduction of the problem with instructions

https://codesandbox.io/s/primereact-test-vzsde has everything demonstrated, but the following steps were followed:

• create a datatable with some data (make sure there are a large number of columns)
• mark the first few columns as frozen
• create fromColumnHeaderGroup and a headerGroup (not sure if multiple rows make a difference, but our project requires multiple rows

Please tell us about your environment:

Windows 10, Visual Code, NPM, Node

• React version:

16.12.0

• PrimeReact version:

3.4.0

• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]

assume all - tried it on Chrome 80, Firefox 72, IE11, Edge 82

• Language: [all | TypeScript X.X | ES6/7 | ES5]
  Typescript