DataTable expanded rows collapse when modifying one property of a record

[winterspan]

I'm submitting a ...

[X] bug report
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://forum.primefaces.org/viewforum.php?f=57
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**Current behavior**
If you are using the row expansion feature, and saving the expanded row data in the state (as demonstrated here https://www.primefaces.org/primereact/#/datatable/rowexpand), all of the expanded rows will collapse if any of the records' fields are changed when passing them in from Redux. 

It seems like the table loses track of the mapping between the expanded row data and the modified record data being passed in as a prop to 'values'. 

**Expected behavior**
Expanded rows should not collapse when the records passed in to the table are not new, just one or more fields modified.

**Minimal reproduction of the problem with instructions**
1) Setup Prime React DataTable with expander column. Records should be provided from redux state slice.
2) expand row
3) have a button in the expanded row update a field on one of the records through a redux action/reducer.
4) You'll notice the row collapses, despite the expandedRowData still being present.

https://codesandbox.io/s/m752k9jq8y

**Please tell us about your environment:**
Windows/IntelliJ/Tomcat

* **React version:**
16.8.3

* **PrimeReact version:**
2.0.1

* **Browser:**
ALL 
 
* **Language:**
ES6/7

[cagataycivici]

This is expected, we need to keep a key of the records that does not change to uniquely identify it so that if a property changes it is still displayed as expanded.

[cagataycivici]

With 3.1.4, expandedRows can work with dataKeys so if you define a dataKey problem will be resolved.

[winterspan]

With 3.1.4, expandedRows can work with dataKeys so if you define a dataKey problem will be resolved.

Excellent. I had just forked the project and started implementing a key based approach. Will give 3.1.4 a try. Thanks