Add ability to show and hide "merged" sidebar
Sometimes, when entering notes with two documents in view, I would like to hide quickly the merged panel to see more of the score. Currently, one can show and hide each of the vertical panels (e.g., inspector, pallets, selection filter, play panel) independently either through the View menu or with a shortcut. Since they are often more than one panel merged, I suggest adding a toggle command (e.g., Show/Hide Sidebar) , with a shortcut, to show or hide all the merged panels at once. (Alternatively, there could be a command to hide all panels, regardless if they have been merged or not). A real life example, given by Jeetee, is the Vivaldi browser. which has a 'sidebar hide/show' command for this besides the individual show/hide panels within the sidebar.
As Marc Sabatella suggested, a workaround for now is to create a custom workspace with the side panels hidden and select the "GUI Components" option.