RFR: 8087555: [ChoiceBox] uncontained value not shown

[Ambarish Rapte]

On Fri, 24 Apr 2020 15:07:59 GMT, Jeanette Winzenburg <fastegal at openjdk.org> wrote:

> Which seems to be hinted at in a code comment in `SingleSelectionModel.select(item)`:

I agree that selectedIndex should be -1 for an uncontained value, so that the below condition always holds true. And
this is already working well with ComboBox.

`assertEquals(getItems().indexOf(selectedItem), selectedIndex)`

The fix for [JDK-8241999](https://bugs.openjdk.java.net/browse/JDK-8241999) would solve most of the behavior
differences of contained Vs uncontained item selection. (that I was looking at selectPrevious(), selectNext()).




> true, that's spec'ed in ComboBox only .. so by analogy I considered it being the same here. Hmm .. might need an update
> of the doc?

Thanks for the the pointer, After reading it, I have a doubtful understanding about it as, that,

The spec is only about `ComboBox.valueProperty()` and not about `SelectionModel.selectedIndex` or
`SelectionModel.selectedItem`. so clearSelection() can/should clear the SelectionModel state but should not clear
ComboBox.valueProperty().

And ComboBox does not follow this spec,
In below scenario `ComboBox.valueProperty()` is cleared to NULL.

`comboBox.getSelectionModel().select(comboBox.getItems(1));`
`comboBox.getSelectionModel().clearSelection();`     => clears the SelectionModel.selectedIndex to -1,
SelectionModel.selectedItem and ComboBox.getValue() to NULL.

So I think, for ChoieBox, In addition to doc change we would need fix the behavior as well,  and maintain same behavior
of `clearSelection()` with contained and uncontained items.

But again this is a different issue and not related to this fix.

So the fix itself looks good to me along with the upcoming fix for
[JDK-8241999](https://bugs.openjdk.java.net/browse/JDK-8241999).

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PR: https://git.openjdk.java.net/jfx/pull/191