MultiView FXML Project on iOS using Gluon-mobile a

Creating a completely new MultiView FXML Project and then adding the Java9 necessities in Gradle:

buildscript {
    repositories {
        jcenter()
        google()
        maven{
            url 'http://nexus.gluonhq.com/nexus/content/repositories/releases'
        }
    }
    dependencies {
        classpath 'org.javafxports:jfxmobile-plugin:2.0.5'
    }
}

...

sourceCompatibility = 1.8
targetCompatibility = 1.8

...

dependencies {
    compile 'com.gluonhq:charm:4.4.0-jdk9'
    androidRuntime 'com.gluonhq:charm:4.4.1'
    compile 'com.airhacks:afterburner.mfx:1.6.3'

    // Added because of javax.annotation.PostConstruct Java9 issues
    compile group: 'javax.xml.ws', name: 'jaxws-api', version: '2.2.6'    
}

leads to [SUB] Exception in thread "JavaFX Application Thread" java.lang.IllegalStateException: Stage must be showing before making the Dialog visible.

full console log

The project runs as expected on Desktop and Android, but not on iOS simulator and device. I have tried many things, but since this error comes on newly created projects leads me to believe that it's something caused by the interplay of gluon-mobile and Java9.

Bonus: Changing only the jfxmobile-plugin to 2.0.18 fails even compiling with:

[15:08:15:141] com.gluonhq.higgs.Higgs: Still compiling... 8823 classes left.
[15:08:25:143] com.gluonhq.higgs.Higgs: Still compiling... 4152 classes left.
[15:08:34:389] com.gluonhq.higgs.Compiler: halfway done round 0 java.lang.StackOverflowError
at java.base/java.util.HashMap.putVal(HashMap.java:642)
at java.base/java.util.HashMap.put(HashMap.java:612)
at java.base/java.util.HashSet.add(HashSet.java:220)
at com.gluonhq.higgs.DependencyGraph.visitReachableNodes(DependencyGraph.java:170)

These steps work for me:

Using Java 9, and NetBeans 9 (beta version) with Gluon IDE plugin 2.6.2, I've created a Gluon project (multi view with FXML). Of course, this will work with other IDEs as well.
I've checked that the gradle wrapper was using 4.3.1 (or superior).
I've modified the build.gradle file to use Gluon VM with jfxmobile 2.0.18:

build.gradle file:

buildscript {
    repositories {
        jcenter()
        google()
        maven {
            url 'http://nexus.gluonhq.com/nexus/content/repositories/releases'
        }
    }
    dependencies {
        classpath 'org.javafxports:jfxmobile-plugin:2.0.18'
    }
}

and updated the dependencies:

sourceCompatibility = 1.8
targetCompatibility = 1.8

dependencies {
    compile 'com.gluonhq:charm:4.4.0-jdk9'
    compile 'com.airhacks:afterburner.mfx:1.6.3'
    compile 'javax.annotation:javax.annotation-api:1.3.2'
    androidRuntime 'com.gluonhq:charm:4.4.1'
}

Then I just deployed the project to my iOS device without any issue.

Note that it may be convenient to clean your ~/.gvm cache, as it might contain classes from older versions that shouldn't be used anymore. Of course, you should also clean your project ./gradle and /build folders.