docs: add warning about unreliable behaviour of scrollToIndex(int) in TreeGrid

[sosa-vaadin]

Description

The scrollToIndex(int) method in TreeGrid is directly inherited from Grid but has some issues. The grid needs to know the entire tree structure to accurately calculate a node's index (in a pre-order traversal method). Since it uses lazy loading for performance reasons, there is no reliable way to consistently scroll to a node's position.

Let's document this behavior in the TreeGrid class version of the method and discourage the use of it until we find a proper solution.

Related: vaadin/web-components#1016, #3505

[manolo]

Shouldn't this be cherry-picked to 20.0 ?

[vaadin-bot]

SonarQube analysis reported 17 issues

• 3 critical
• 3 major
• 3 minor
• 8 info

Top 10 issues

1. TreeGrid.java#L291: Define a constant instead of duplicating this literal "TreeGrid only accepts hierarchical data providers. " 6 times.
2. TreeGrid.java#L292: Define a constant instead of duplicating this literal "An example of interface to be used: HierarchicalDataProvider" 6 times.
3. TreeGrid.java#L334: Define a constant instead of duplicating this literal "Use another setDataProvider/setItems method instead with hierarchical data." 5 times.
4. TreeGrid.java#L656: Call "Optional#isPresent()" before accessing the value.
5. TreeGrid.java#L657: Either log or rethrow this exception.
6. TreeGrid.java#L673: Either log or rethrow this exception.
7. TreeGrid.java#L201: Move this constructor to comply with Java Code Conventions.
8. TreeGrid.java#L311: Remove this use of "setDataProvider"; it is deprecated.
9. TreeGrid.java#L956: Remove this method to simply inherit it.
10. TreeGrid.java#L330: Do not forget to remove this deprecated code someday.