I am trying to set an "on replace" trigger on the selectedItem public variable in the following way :
SwingComboBox {
...
override var selectedItem on replace {
...
}
It allows to be notified of selection change.
When the Stage that contains this ComoboBox is displayed, the pasted Exceptions occurs and the Stage is NOT displayed.
Overriding this public field seems valid.
I tried with TextBox, and the same problem occured...
I attached a simple, self-contained testcase that shows it all.


Exception in trigger:
java.lang.NullPointerException
        at com.sun.scenario.scenegraph.SGText.getEols(SGText.java:579)
        at com.sun.scenario.scenegraph.SGText.setText(SGText.java:363)
        at javafx.scene.text.Text$1.onChange(Text.fx:69)
        at javafx.scene.text.Text$1.onChange(Text.fx:68)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:165)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:162)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:55)
        at com.sun.javafx.runtime.location.ObjectVariable.notifyListeners(ObjectVariable.java:162)
        at com.sun.javafx.runtime.location.ObjectVariable.replaceValue(ObjectVariable.java:117)
        at com.sun.javafx.runtime.location.ObjectVariable.update(ObjectVariable.java:145)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:179)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidate(AbstractLocation.java:115)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:177)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidate(AbstractLocation.java:115)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:177)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:72)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidate(AbstractLocation.java:115)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:177)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidate(AbstractLocation.java:115)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:177)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)

        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.ObjectVariable.notifyListeners(ObjectVariable.java:160)
        at com.sun.javafx.runtime.location.ObjectVariable.replaceValue(ObjectVariable.java:117)
        at com.sun.javafx.runtime.location.ObjectVariable.set(ObjectVariable.java:128)
        at javafx.scene.control.Control$18.onChange(Control.fx:72)
        at javafx.scene.control.Control$18.onChange(Control.fx:70)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:165)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:162)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:55)
        at com.sun.javafx.runtime.location.ObjectVariable.notifyListeners(ObjectVariable.java:162)
        at com.sun.javafx.runtime.location.ObjectVariable.replaceValue(ObjectVariable.java:117)
        at com.sun.javafx.runtime.location.ObjectVariable.set(ObjectVariable.java:128)
        at javafx.scene.control.TextBox.applyDefaults$skin(TextBox.fx:85)
        at javafxapplication3.Main$1TextBox$anon1.applyDefaults$skin(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.applyDefaults$skin(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.initialize$(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.initialize$(Main.fx:39)
        at javafxapplication3.Main.javafx$run$(Main.fx:39)
        at javafxapplication3.Main.javafx$run$(Main.fx:39)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at com.sun.javafx.runtime.provider.AWT_EDT_RuntimeProvider$1.run(AWT_EDT_RuntimeProvider.java:102)
        at java.awt.event.InvocationEvent.dispatch(Unknown Source)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)
Exception in trigger:
java.lang.NullPointerException
        at com.sun.scenario.scenegraph.SGText.getEols(SGText.java:579)
        at com.sun.scenario.scenegraph.SGText.setText(SGText.java:363)
        at javafx.scene.text.Text$1.onChange(Text.fx:69)
        at javafx.scene.text.Text$1.onChange(Text.fx:68)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:165)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:162)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:55)
        at com.sun.javafx.runtime.location.ObjectVariable.notifyListeners(ObjectVariable.java:162)
        at com.sun.javafx.runtime.location.ObjectVariable.replaceValue(ObjectVariable.java:117)
        at com.sun.javafx.runtime.location.ObjectVariable.update(ObjectVariable.java:145)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:179)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidate(AbstractLocation.java:115)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:177)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:72)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.ObjectVariable.notifyListeners(ObjectVariable.java:160)
        at com.sun.javafx.runtime.location.ObjectVariable.setDefault(ObjectVariable.java:135)
        at javafx.scene.control.TextBox.applyDefaults$text(TextBox.fx:37)
        at javafxapplication3.Main$1TextBox$anon1.applyDefaults$text(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.applyDefaults$text(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.initialize$(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.initialize$(Main.fx:39)
        at javafxapplication3.Main.javafx$run$(Main.fx:39)
        at javafxapplication3.Main.javafx$run$(Main.fx:39)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at com.sun.javafx.runtime.provider.AWT_EDT_RuntimeProvider$1.run(AWT_EDT_RuntimeProvider.java:102)
        at java.awt.event.InvocationEvent.dispatch(Unknown Source)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)
HELLO 2
Failed to parse style border-fill:null; background-fill:#00000000; focus-fill:null on node TextBox$anon1 [boundsInLocal=Rectangle2D [minX = 0.0, minY=0.0, maxX=0.0, maxY=0.0, width=0.0, height=0.0], boundsInParent=Rectangle2D [minX = 0.0, minY=0.0, maxX=0.0, maxY=0.0, width=0.0, height=0.0]
com.sun.stylesheet.StylesheetException: java.lang.reflect.InvocationTargetException
        at com.sun.stylesheet.types.TypeManager.getStyleable(TypeManager.java:302)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:253)
        at javafx.scene.Node.updateCSS$impl(Node.fx:473)
        at javafxapplication3.Main$1TextBox$anon1.updateCSS(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.updateCSS(Main.fx:39)
        at javafx.scene.Node.postInit$(Node.fx:590)
        at javafx.scene.CustomNode.postInit$(CustomNode.fx:56)
        at javafx.scene.control.Control.postInit$(Control.fx:55)
        at javafx.scene.control.TextBox.postInit$(TextBox.fx:29)
        at javafxapplication3.Main$1TextBox$anon1.postInit$(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.postInit$(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.initialize$(Main.fx:39)
        at javafxapplication3.Main$1TextBox$anon1.initialize$(Main.fx:39)
        at javafxapplication3.Main.javafx$run$(Main.fx:39)
        at javafxapplication3.Main.javafx$run$(Main.fx:39)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at com.sun.javafx.runtime.provider.AWT_EDT_RuntimeProvider$1.run(AWT_EDT_RuntimeProvider.java:102)
        at java.awt.event.InvocationEvent.dispatch(Unknown Source)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
        at java.lang.reflect.Constructor.newInstance(Unknown Source)
        at com.sun.stylesheet.types.TypeManager.getStyleable(TypeManager.java:287)
        ... 23 more
Caused by: com.sun.stylesheet.StylesheetException: java.lang.reflect.InvocationTargetException
        at com.sun.stylesheet.types.TypeManager.getStyleSupport(TypeManager.java:348)
        at com.sun.stylesheet.styleable.DefaultStyleable.getStyleSupport(DefaultStyleable.java:124)
        at com.sun.stylesheet.styleable.DefaultStyleable.<init>(DefaultStyleable.java:73)
        ... 28 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
        at java.lang.reflect.Constructor.newInstance(Unknown Source)
        at com.sun.stylesheet.types.TypeManager.getStyleSupport(TypeManager.java:333)
        ... 30 more
Caused by: java.lang.NullPointerException
        at javafx.reflect.FXLocal$SortedClassArray.insert(FXLocal.java:552)
        at javafx.reflect.FXLocal$ClassType.getSuperClasses(FXLocal.java:316)
        at javafx.reflect.FXLocal$ClassType.getSuperClasses(FXLocal.java:334)
        at com.sun.stylesheet.javafx.FXObjectStyleSupport.<init>(FXObjectStyleSupport.java:162)
        ... 35 more
HELLO
com.sun.stylesheet.StylesheetException: java.lang.reflect.InvocationTargetException
        at com.sun.stylesheet.types.TypeManager.getStyleable(TypeManager.java:302)
        at com.sun.stylesheet.javafx.FXObjectStyleSupport.getStyleableChildren(FXObjectStyleSupport.java:243)
        at com.sun.stylesheet.styleable.DefaultStyleable.getStyleableChildren(DefaultStyleable.java:171)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:279)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:257)
        at javafx.scene.Scene.userInit$(Scene.fx:212)
        at javafx.scene.Scene.initialize$(Scene.fx:40)
        at javafxapplication3.Main.javafx$run$(Main.fx:37)
        at javafxapplication3.Main.javafx$run$(Main.fx:37)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
        at java.lang.reflect.Constructor.newInstance(Unknown Source)
        at com.sun.stylesheet.types.TypeManager.getStyleable(TypeManager.java:287)
        at com.sun.stylesheet.javafx.FXObjectStyleSupport.getStyleableChildren(FXObjectStyleSupport.java:243)
        at com.sun.stylesheet.styleable.DefaultStyleable.getStyleableChildren(DefaultStyleable.java:171)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:279)
        at com.sun.stylesheet.Stylesheet.applyTo(Stylesheet.java:257)
        at javafx.scene.Scene.userInit$(Scene.fx:212)
        at javafx.scene.Scene.initialize$(Scene.fx:40)
        at javafxapplication3.Main.javafx$run$(Main.fx:37)
        at javafxapplication3.Main.javafx$run$(Main.fx:37)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at com.sun.javafx.runtime.provider.AWT_EDT_RuntimeProvider$1.run(AWT_EDT_RuntimeProvider.java:102)
        at java.awt.event.InvocationEvent.dispatch(Unknown Source)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: com.sun.stylesheet.StylesheetException: java.lang.reflect.InvocationTargetException
        at com.sun.stylesheet.types.TypeManager.getStyleSupport(TypeManager.java:348)
        at com.sun.stylesheet.styleable.DefaultStyleable.getStyleSupport(DefaultStyleable.java:124)
        at com.sun.stylesheet.styleable.DefaultStyleable.<init>(DefaultStyleable.java:73)
        ... 25 more
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
        at java.lang.reflect.Constructor.newInstance(Unknown Source)
        at com.sun.stylesheet.types.TypeManager.getStyleSupport(TypeManager.java:333)
        ... 27 more
Caused by: java.lang.NullPointerException
        at javafx.reflect.FXLocal$SortedClassArray.insert(FXLocal.java:552)
        at javafx.reflect.FXLocal$ClassType.getSuperClasses(FXLocal.java:316)
        at javafx.reflect.FXLocal$ClassType.getSuperClasses(FXLocal.java:334)
        at com.sun.stylesheet.javafx.FXObjectStyleSupport.<init>(FXObjectStyleSupport.java:162)
        ... 32 more
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