Tornadofx: IndexOutOfBoundsException while adding step to a Wizard

[jagiellonczyk14]

I asynchronously prepare wizard and when ready I Dock it to a workspace. however I have some strange problem when trying to add second step - when I am using wizard with single step everything is working fine, the problem arises only when I wan to add a second one - it gives error posted below.
What is funny Although I get the error, the program seems to work fine when I only close the error window and both steps are added to Wizard and working

Invoking Wizard

val bigTarczycaWiztoList:  Deferred<bigTarczycaWizard> = async{ bigTarczycaWizard( )  }
    init {
        bigTarczycaWiztoList.invokeOnCompletion {
              async{   bigTarczycaWiztoList.await().controlleerr =bigTarczycaController() }
            }}

    fun bigTarczycaWizDock() {
         if(bigTarczycaWiztoList.isCompleted) {  workspace.dock(bigTarczycaWiztoList.getCompleted(), true)
         } else {
         bigTarczycaWiztoList.invokeOnCompletion {workspace.dock(bigTarczycaWiztoList.getCompleted(), true) }

         }
    }

Wizard

class bigTarczycaWizard () : MyWizard("Tarczyca Tc", "Opis Badania") {
    init {

        graphic = imageview("graphics/Webp.net-resizeimage.jpg")
        add(bigTarczycaStep1():: class)
        add(bigTarczycaStep2() :: class)
    } }

Error

java.lang.IndexOutOfBoundsException: Index: 1, Size: 0
    at java.util.AbstractList.rangeCheckForAdd(AbstractList.java:605)
    at java.util.AbstractList.addAll(AbstractList.java:257)
    at javafx.collections.ModifiableObservableListBase.addAll(ModifiableObservableListBase.java:110)
    at com.sun.javafx.collections.VetoableListDecorator.addAll(VetoableListDecorator.java:252)
    at tornadofx.ListConversionListener.onChanged(Collections.kt:231)
    at com.sun.javafx.collections.ListListenerHelper$Generic.fireValueChangedEvent(ListListenerHelper.java:329)
    at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
    at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
    at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
    at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
    at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
    at javafx.collections.ModifiableObservableListBase.add(ModifiableObservableListBase.java:155)
    at java.util.AbstractList.add(AbstractList.java:108)
    at tornadofx.FXKt.addChildIfPossible(FX.kt:494)
    at tornadofx.FXKt.addChildIfPossible$default(FX.kt:454)
    at tornadofx.NodesKt.plusAssign(Nodes.kt:228)
    at tornadofx.UIComponent.add(Component.kt:685)
    at tornadofx.UIComponent.add$default(Component.kt:683)
    at implementation.BigFragControllers.bigTarczycaWizard.<init>(bigTarczycaController.kt:159)
    at implementation.menu.MenuControllersList$bigTarczycaWiztoList$1.doResume(MenuControllersList.kt:15)
    at kotlin.coroutines.experimental.jvm.internal.CoroutineImpl.resume(CoroutineImpl.kt:54)
    at kotlinx.coroutines.experimental.DispatchedTask$DefaultImpls.run(Dispatched.kt:161)
    at kotlinx.coroutines.experimental.DispatchedContinuation.run(Dispatched.kt:25)
    at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402)
    at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
    at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

[edvin]

I haven't look at your code, but JavaFX components _must_ be created on the UI thread. You simply can't create them on a background thread, so I suspect this is what's causing the error. Please confirm :)

[jagiellonczyk14]

Thank You for fast response, Hovewer in this case I suppose hat it is not a problem because
1) It would give the same error when I am adding Wizard with only one step - and It is not the case - until I have one step wizard everything works fine
2) It will not only cause error, but this error would break a program - and It did not happene also - Error appears but , just after shutting down window with error stacktrace I have a working application with docked wizard with 2 steps. Although maybe I have not spotted some component that is not working.

[edvin]

Can you supply some demo code which exhibits this issue, something runnable without any async code in it?

[jagiellonczyk14]

It was very good idea to create sample app, during the process of this I have found up that I messed up while creating my implementation of a Wizard (I did not wanted a cancel button), Hovewer now when I got back to original Wizard everythink works fine including async preparation of wizard
Thanks for help!

[edvin]

Fantastic :) It wasn't my intention to be lazy, but it would be hard to debug based on the previous code sample and now we got some real value from it :) Feel free to post the code you created to test!

[nimakro]

Will close because of inactivity