Making minimised windows work like hidden ones, plus an optional "Minimised" OmniShell widget

[CarlitoGrey]

Summary

Hidden apps (⌘H) work really well in OmniWM. Minimised windows don't yet: you can't get one back from the workspace bar. I'd like to suggest two steps:

1. A fix: treat minimised windows like hidden ones. Give them their own marker on the bar, and have a click restore the window to its original workspace.
2. An option: an opt-in "Minimised" OmniShell widget that shows the same list on every monitor's bar. A window you minimise moves into the widget, and clicking it there restores it to the workspace you're on now. Turning the option on adds the widget to your bar automatically.

I'd like to agree the direction before writing step 2.

How hidden apps work today

• Hiding is per app. Each window keeps its workspace and leaves the layout.
• The workspaces widget keeps the window under its workspace, marks it as hidden, and sorts it after visible apps.
• Clicking it unhides the app and takes you to the window on its original workspace.

It's predictable and it fits a tiling workflow.

How minimised windows behave today

• OmniWM sees the minimise through AX. The window keeps its workspace and leaves the layout, just like a hidden one.
• The workspaces widget shows it exactly like a normal window. Its data has a hidden flag but no minimised one.
• Clicking it does nothing. The bar's focus path never un-minimises the window. It also skips windows that macOS has minimised, and macOS ignores activate and raise for a minimised window anyway. The only ways back are the Dock, ⌘⌥Tab or the app's Window menu.

Step 1: make minimise behave like hidden

• Pass a minimised flag (and count) to the workspaces widget alongside hidden, and give minimised windows their own marker, distinct from the hidden one, so you can see at a glance what's minimised.
• Clicking a minimised window un-minimises it and takes you to it on its original workspace, the same as clicking a hidden app.

I have a small PR ready for the click part. focusWindowFromBar clears the window's minimised state before focusing it, and it comes with tests. I'll open it separately, since it fixes today's behaviour whichever way this discussion goes. The bar marker would be a follow-up.

Step 2: an optional "Minimised" widget

Some windows are transient: a chat, a download, a call, a log you want to glance at. For those, returning the window to wherever it came from isn't really what you want. You want to pull it onto the workspace in front of you, check it, and put it away again. That's also how macOS treats minimised windows by default: a window restored from the Dock appears on the Space you're on now.

The idea:

• A setting, for example minimizedWindows.restoreTo = "origin" | "current". The default stays "origin" (step 1), so nothing changes for anyone who doesn't opt in.
• With "current", minimised windows leave their workspace's list in the workspaces widget and appear in a new bundled minimized widget instead. The widget shows the same list on every monitor's bar.
• Turning the option on adds the widget to the bar automatically, the same way the System Stats button does today. setSystemStatsEnabled appends systemStatsWidget to the trailing lane if it isn't already placed. Here, shell.toml would name minimizedWidget = "minimized", and enabling the option would add it after workspaces in the leading lane unless the user has already placed it. People who want it somewhere else can move it like any other widget.
• If the option is on but the widget has been removed from the bar, minimised windows should go back to showing under their workspace (step 1 behaviour), so they never disappear from the bar completely.
• Clicking a window in the widget un-minimises it and moves it into the active workspace on the monitor whose bar you clicked. To restore it on another monitor, you click it on that monitor's bar.
• Tiled windows go in next to the focused window. Floating windows keep their size.
• Shift-click restores the window as floating, so you can glance at a transient window without reshuffling your tiles. If it was floating before, it goes back to its last floating frame. Otherwise it's centred on the current monitor at the size it had before it was minimised. A window that was already floating just restores as normal. The widget's right-click menu would offer "Restore" and "Restore as floating" too, so the option is easy to find and doesn't depend on a modifier key.
• A window restored some other way (the Dock, ⌘⌥Tab, the Window menu) follows the same setting, so the result doesn't depend on how you brought it back.

Why not a new kind of workspace? I thought about modelling this as a special workspace you can't switch to. But every workspace path would then need a guard: switching workspaces, moving windows, monitor assignment, layouts, IPC, swipes and overview. A minimised window already sits outside the layout. The only new decision is which workspace it goes back to when it's restored, so a widget plus a choice at restore time seems much simpler.

Hidden apps stay as they are. Hiding covers every window of an app at once, so "put them all back where they were" is right for hiding. If a window is minimised and its app is hidden, it sits in the Minimised widget. Clicking it brings back just that window, and the app's other windows reappear on their own workspaces.

Questions for maintainers

1. Are you happy with step 1 (a minimised marker, with a click restoring the window to its original workspace) as the default?
2. Would you take step 2 as an opt-in setting?
3. Is auto-adding the widget when the option is turned on (like the System Stats button) the right pattern, and is "after workspaces in the leading lane" a sensible default spot?
4. For shift-click, would you prefer a single "restore" request with a floating option, or should the widget chain the existing window toggle-floating and focus requests? I'd lean towards the single request, so the window never shows up tiled for a moment before it floats.
5. Would a "minimise focused window" command be welcome alongside it? OmniWM doesn't have one at the moment.

Related: #143, #688

[CarlitoGrey]

@BarutSRB when you get a moment I'd appreciate your thoughts on this for overall direction. tl;dr, minimised windows handled like hidden with an icon in the bar, toggle optiion to move minimised windows to a special workspace in the bar which can then be restored on whichever active workspace when clicked.

[BarutSRB]

Step 1 is welcome against the shared workspaces widget; the click restoration already landed in #895. Step 2 overlaps scratchpads for transient windows, but automatically handling native minimization would be new behavior. I suggest deferring that until after 0.8.0, including its placement and restore API decisions. The minimize command can be considered separately. Sorry I'm just a bit busy with the release for 0.8.0 but 100% I'll look at it closer after the release. Thank you ♥️