RFR: 8277122: SplitPane divider drag can hang the layout [v4]

[Ajit Ghaisas]

On Thu, 27 Jan 2022 20:48:40 GMT, Marius Hanl <mhanl at openjdk.org> wrote:

>> When a divider is moved via drag or code it will call **requestLayout()** for the **SplitPane**.
>> While this is fine, it is also called when the **SplitPaneSkin#layoutChildren(..)** method is repositioning the divider.
>> 
>> This makes no sense since we are currently layouting everything, so we don't need to request it again. (The divider positioning is the first part of **layoutChildren(..)**. In the second part the SplitPane content is layouted based off those positions)
>> 
>> -> With this behaviour the layout may hang under some conditions (check attached source). The problem is that the **requestLayout()** will mark the **SplitPane** dirty but won't propagate to the parent since the **SplitPane** is currently doing a layout.
>> 
>> This PR fixes this by not requesting layout when we are currently doing it (and thus repositioning the dividers as part of it).
>> 
>> Note: I also fixed a simple typo of a private method in SplitPaneSkin:
>> initializeDivderEventHandlers -> initializeDiv**i**derEventHandlers
>
> Marius Hanl has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8277122: Added and used global stageLoader + changed copyright year to 2022

The fix looks good. +1.

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Marked as reviewed by aghaisas (Reviewer).

PR: https://git.openjdk.java.net/jfx/pull/669