https://forum.plantuml.net/19823/allowmixing-has-side-effect-on-remove?show=19827
"allowmixing" has side-effect on remove - PlantUML Q&A
When "allowmixing" is set on a diagram, then the "remove" command does not work on nested ... nested element has no ' effect. remove trara @enduml
side effectremoveplantumlq