After a lot of trial and error I realize it is not really possible to have MDI out of the box. The furthest I could get was setting a MultiViewPageDescriptor as part of my application lifecycle but this only means I simply have a SDI application with multiple views and not really JInternalFrames when I activate a view using: applicationConfig.windowManager().getActiveWindow().getPage().showView(ViewID);
After a lot of trial and error I realize it is not really possible to have MDI out of the box. The furthest I could get was setting a MultiViewPageDescriptor as part of my application lifecycle but this only means I simply have a SDI application with multiple views and not really JInternalFrames when I activate a view using: applicationConfig.windowManager().getActiveWindow().getPage().showView(ViewID);