When you turn on the Portal pane, e.g. Start > Desktop > Design > Portal
its not immediately obvious how to make it go away again
* it doesnt toggle away
* it doesn't have the usual push pin or close (x) control
* the hamburger menu doesn't help
Turns out you have to RMB on the "Portal" title bar to find the context menu which lets you autohide it.
Suggestion: Have the Portal pane follow the UI conventions of other panes,
thus reducing the pain
Reported