Any call to the native command "open" used to open a file (CSS) or a URL (Help, CSS reference), or to reveal a file in the Finder (CSS, resource bundle), fails on Mac (and only there).

More specifically, this will prevent the following commands to work:
 - File > Reveal in Finder
 - Preview > Scene Style Sheets > Open a Style Sheet
 - Preview > Internationalization > Reveal Resource
 - Help > Scene Builder Help
 - Open/Reveal CSS files from Inspector panel and from CSS Analyzer panel

In some cases, the attempted operation will return the following error, in other cases it will fail silently:
java.io.IOException: Cannot run program "open": error=0, spawn failed
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1042)
at com.oracle.javafx.scenebuilder.kit.editor.EditorPlatform.executeDaemon(EditorPlatform.java:228)
at com.oracle.javafx.scenebuilder.kit.editor.EditorPlatform.open(EditorPlatform.java:139)
at com.oracle.javafx.scenebuilder.app.DocumentWindowController.performHelp(DocumentWindowController.java:1559)
at com.oracle.javafx.scenebuilder.app.DocumentWindowController.performControlAction(DocumentWindowController.java:656)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$DocumentControlActionController.perform(MenuBarController.java:1392)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController.handleOnActionMenu(MenuBarController.java:957)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController.access$800(MenuBarController.java:86)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$15.handle(MenuBarController.java:950)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$15.handle(MenuBarController.java:946)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:204)
at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
at com.sun.javafx.scene.control.GlobalMenuAdapter$5.handle(GlobalMenuAdapter.java:158)
at com.sun.javafx.scene.control.GlobalMenuAdapter$5.handle(GlobalMenuAdapter.java:156)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:204)
at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
at com.sun.javafx.tk.quantum.GlassSystemMenu$6.action(GlassSystemMenu.java:234)
Caused by: java.io.IOException: error=0, spawn failed
at java.lang.UNIXProcess.forkAndExec(Native Method)
at java.lang.UNIXProcess.<init>(UNIXProcess.java:185)
at java.lang.ProcessImpl.start(ProcessImpl.java:134)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1023)
... 30 more