Even with the fix for JDK-8266643 we are still seeing occasional failures in HonorDeveloperSettingsTest. See, for example:

https://github.com/kevinrushforth/jfx/runs/2622717440

Here is the failure:

2021-05-19T17:31:28.3107034Z test.javafx.css.HonorDeveloperSettingsTest > testOpacityWithManuallyChangedValueAndInlineStyleIsSetToInlineStyle FAILED
2021-05-19T17:31:28.3110123Z java.lang.NullPointerException: Cannot invoke "javafx.scene.Parent.isDirty(com.sun.javafx.scene.DirtyBits)" because "root" is null
2021-05-19T17:31:28.3112077Z at javafx.graphics/javafx.scene.Node.notifyParentsOfInvalidatedCSS(Node.java:9295)
2021-05-19T17:31:28.3113561Z at javafx.graphics/javafx.scene.Node.reapplyCSS(Node.java:9342)
2021-05-19T17:31:28.3114647Z at javafx.graphics/javafx.scene.Node$1.reapplyCSS(Node.java:588)
2021-05-19T17:31:28.3115989Z at javafx.graphics/com.sun.javafx.scene.NodeHelper.reapplyCSS(NodeHelper.java:283)
2021-05-19T17:31:28.3120682Z at javafx.graphics/com.sun.javafx.css.StyleManager.userAgentStylesheetsChanged(StyleManager.java:1514)
2021-05-19T17:31:28.3123014Z at javafx.graphics/com.sun.javafx.css.StyleManager.setDefaultUserAgentStylesheet(StyleManager.java:1365)
2021-05-19T17:31:28.3125364Z at javafx.graphics/com.sun.javafx.css.StyleManager.setDefaultUserAgentStylesheet(StyleManager.java:1347)
2021-05-19T17:31:28.3127674Z at test.javafx.css.HonorDeveloperSettingsTest.setUp(HonorDeveloperSettingsTest.java:90)