The Cylc GUI now preserves tab layout between sessions.
When working on a workflow, we can open multiple tabs (tree, table, graph, etc) and tile them up in a layout. If you switch to another workflow, switch back, your layout will be restored.
However, with Cylc 8.4, if you refreshed the browser or opened the GUI in a new tab, the layout would be lost.
With Cylc 8.5, the layout will always be restored.