Visualisations don't unsubscribe properly

Clicking a node after closing a visualisation throws a one time error because for some reason it tries to select a node on the removed visualisation. Possibly because that visualisation is still subscribed to receive node selection events.

Steps to reproduce this:

• Open 2 visualisations
• Close one of them
• Click any node on the remaining visualisation
• There should be an error from the closed visualisation in the console.