Plasmoidviewer opens windows outside of the viewer?

So, I’m doing some plain old testing of the kickoff plasmoid, and so I run:
‘plasmoidviewer -a org.kde.plasma.kickoff’

Then, when I press on the icon, the apps pop open in a window outside of the plasmoidviewer… Why? Shouldn’t these act in a similar way so that we can develop properly!?

Screenshot atached…