Choose Work
Choose Work from the Interaction control. Custom placement is a Work mode tool.
Place bubbles in the node network
With Custom placement on, drag any open bubble or any theme to where you want it. It keeps that place, and returns there each time it shows.
Tip: In other modes you can drag a bubble aside to see what is behind it, but it springs back when you let go.
Reorder the hierarchy or file tree
In Hierarchy or File tree, drag a box or row to a new place among its neighbours. The new order is kept, and each view keeps its own order.
Clear an arrangement
Clear arrangement returns a view to its usual order, or every placed bubble to its usual place.
Save your progress
Your arrangements go into the layout file when you save your progress. It holds names and places, never your quotes.