RFR: 8267392: ENTER key press on editable TableView throws NPE

[Jeanette Winzenburg]

On Wed, 19 May 2021 00:48:18 GMT, Marius Hanl <github.com+66004280+Maran23 at openjdk.org> wrote:

> **Note: I reported the bug already, waiting for approval. Internal tracking id: 9070318. I will update the title as soon as the ticket is created.**
> 
> This PR is fixing a NP, which is thrown when you press ENTER on an editbale table, after it is initially shown.
> 
> When pressing ENTER, **TableViewBehaviorBase#activate** is retrieving the current focused row (**getFocusedCell()**) and from there the corresponding table column.
> This is null, when a table is initially shown. It can also be null, when the items from the underlying table are changed (e.g. **setItems()**) or when **getFocusModel().focus(row)** is used. 
> Therefore, null is a valid value and we should guard against it.

sounds like a duplicate of [JDK-8089652](https://bugs.openjdk.java.net/browse/JDK-8089652)  - faintly remember that it's a dark pit: there are issues in selection/focus model implementations, see f.i. [JDK-8219720](https://bugs.openjdk.java.net/browse/JDK-8219720). Starting with fixing the NPE is goood :))

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PR: https://git.openjdk.java.net/jfx/pull/505