Cinnamon Sidebar

Dock a single window to the left or right edge of a monitor at a configurable width. Other windows are kept out of the reserved area, so a docked window behaves like a real sidebar: the rest of the screen stays usable and nothing covers the dock.

Features

• Panel button lists every window on the current workspace. Click one to dock it to the configured side; click it again (marked ✓) to undock.
• Configurable dock side — Left or Right. Changing the side or width while a window is docked moves/resizes it live.
• Configurable width — a fraction of the monitor width, or a fixed pixel value.
• Keyboard shortcuts (configurable):
  • Super+Shift+Left — dock the focused window to the configured side
  • Super+Shift+Down — undock the docked window (restores its pre-dock size)
• The docked window is locked — it can't be moved, resized, or maximized off its slot. Any attempt snaps it straight back.
• Others are kept out of the dock column — dragging a window into the dock, or maximizing/tiling it, keeps it in the space beside the dock. You can still move a window partially off the opposite screen edge; only the dock edge is protected.
• Maximize toggle — maximizing another window fills the space beside the dock (not the whole screen). Maximizing it again restores its previous size and position.
• Command-line / programmatic control — a D-Bus service lets scripts and programs dock and undock windows (by focus, title, application, or window id). See Command-line / programmatic control (D-Bus).

Usage

1. Add Sidebar Dock to a panel (right-click panel → Applets, or cinnamon-settings applets).
2. Click the panel icon and pick a window to dock, or press the dock shortcut on the focused window.
3. Configure side, width, and shortcuts via the applet's settings (the gear icon next to it in the Applets list).

Command-line / programmatic control (D-Bus)

The applet exports a D-Bus service so any program or script can dock and undock windows without user interaction. Windows are always docked to the side and width configured in the applet's settings.

• Bus name: org.Cinnamon.SidebarDock
• Object path: /org/Cinnamon/SidebarDock
• Interface: org.Cinnamon.SidebarDock

The service is on the session bus and is available whenever the applet is loaded in a panel.

Methods

Each Dock*/Undock method returns a boolean: true when it found a matching window and acted, false otherwise.

ListWindows returns JSON of the form:

{
  "dock_side": "left",
  "windows": [
    {
      "title": "Mozilla Firefox",
      "wm_class": "Navigator",
      "wm_class_instance": "firefox",
      "xid": 54525959,
      "monitor": 0,
      "docked": false
    }
  ]
}

Examples

Using gdbus (ships with GLib):

# Dock the currently focused window
gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.DockFocused

# Undock
gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.Undock

# Dock the first window whose title contains "Firefox"
gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.DockByTitle "Firefox"

# Dock by application (WM_CLASS) — handy right after launching an app
gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.DockByApp "firefox"

# List dockable windows as JSON
gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.ListWindows

The same calls with dbus-send (note the explicit argument types):

dbus-send --session --print-reply \
  --dest=org.Cinnamon.SidebarDock \
  /org/Cinnamon/SidebarDock \
  org.Cinnamon.SidebarDock.DockByApp string:"firefox"

Docking by window id. DockById takes a decimal uint32. wmctrl -l prints ids in hex (e.g. 0x03400007), so convert first:

# Dock a window picked by clicking it (xdotool prints a decimal id)
gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.DockById "$(xdotool selectwindow)"

# From a hex wmctrl id
xid=$(printf '%d' 0x03400007)
gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.DockById "$xid"

Launch an app and dock it once its window appears:

firefox &
# wait for the window, then dock it by class
until gdbus call --session --dest org.Cinnamon.SidebarDock \
  --object-path /org/Cinnamon/SidebarDock \
  --method org.Cinnamon.SidebarDock.DockByApp "firefox" | grep -q true; do
  sleep 0.3
done

How it works

Cinnamon/Muffin has no way to let a normal application window live inside a reserved strut, and a window's type (e.g. DOCK) is set by the application and read-only to extensions. So Sidebar Dock reserves the edge reactively rather than via struts:

• The docked window is placed into a fixed slot recorded once at dock time (its actual size is read back afterwards, since many apps have a minimum width).
• Every other window is watched; if one moves, resizes, maximizes, or tiles so that it would cover the dock column, it is shrunk/shifted back into the band beside the dock. The clamp only protects the dock edge, so windows can still go off the opposite screen edge.
• A window's pre-maximize size is tracked continuously, so the maximize toggle can restore it exactly (Muffin's unmaximize() is asynchronous and can't be read in time otherwise).
• The docked window's own moves are reverted immediately, and interactive drags are settled on grab-op-end (Muffin owns geometry during a grab).

Limitations

• Windows with a minimum width larger than the configured dock width will dock at their minimum width instead.
• The maximize toggle un-maximizes the window to fill the band, so its titlebar button reads maximize rather than restore — but maximizing again restores the previous size.
• Targets the window's current monitor and the active workspace.

Development

The source lives in files/cinnamon-sidebar@beatlink/. To iterate locally, symlink it into the applets directory and reload Cinnamon (Alt+F2 → r → Enter):

ln -sfn "$PWD/files/cinnamon-sidebar@beatlink" \
    ~/.local/share/cinnamon/applets/cinnamon-sidebar@beatlink

Set DEBUG = true at the top of applet.js to trace geometry decisions to ~/.xsession-errors.