I was just testing out HelloComboBox and HelloChoiceBox, and noted that I'm getting a bunch of warnings for various CSS properties when I go to show the popup.

WARNING: com.sun.javafx.css.StyleHelper calculateValue Could not resolve '-fx-box-border' while resolving lookups for '-fx-background-color' from rule '*.list-view' in stylesheet jar:file:/C:/programming/netbeans/Java-FX/artifacts/sdk/rt/lib/jfxrt.jar!/com/sun/javafx/scene/control/skin/caspian/caspian.bss

If assertions are enabled, you get this assertion error. This tracks back to handleControlPropertyChanged (at least in the case of HelloComboBox:

Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.AssertionError
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:250)
at com.sun.glass.ui.View.handleMouseEvent(View.java:523)
at com.sun.glass.ui.View.notifyMouse(View.java:916)
Caused by: java.lang.AssertionError
at com.sun.javafx.css.StyleManager.getStyleHelper(StyleManager.java:773)
at javafx.scene.Node.impl_createStyleHelper(Node.java:7392)
at javafx.scene.Node.impl_processCSS(Node.java:7358)

This is a regression caused by RT-20217