← Otto User GuideTop Bar

otto-bar is Otto’s menu bar: a full-width panel along the top edge of the primary monitor, with frosted-glass blur, rounded bottom corners and a soft shadow.

Starting it

It is a separate program, not part of the compositor. Start it from your config:

[[exec_once]]
cmd = "otto-bar"

See Autostart for other ways to launch it.

Layout

┌──────────────────────────────────────────────────────────────────────┐
│ Firefox  File  Edit  View  Help      (island)      🔊 🔋  Mar 23, 21:16│
└──────────────────────────────────────────────────────────────────────┘
  ← left zone ────────────────►      centre       ← right zone ───────►

Left — the focused application’s name in bold, then its global menu.
Centre — deliberately empty, leaving room for the Dynamic Island.
Right — system tray icons, then the clock.

The bar reserves its own height as an exclusive zone, so maximized windows and other panels stop below it rather than sliding underneath.

Global application menus

The left zone shows the focused window’s menu — File, Edit, View and so on — sourced over D-Bus using the com.canonical.dbusmenu protocol. This is the same mechanism Unity and KDE’s global menu use.

Action	Effect
Click a top-level title	Drop the menu down
`↑` / `↓`	Move through items
`→` / `Enter` on a submenu	Open it
`←`	Back to the parent menu
`Enter`	Activate the highlighted item
`Escape`	Close

Hovering a submenu opens it after a short delay (about 300 ms) rather than instantly, so passing over an item on the way somewhere else does not fire it. Exactly one item is highlighted anywhere in the menu tree at a time.

Menu items support labels, icons, keyboard-shortcut hints, separators, checkboxes, radio groups and arbitrarily nested submenus. Disabled items are dimmed and inert.

Not every application exports a DBusMenu. When one does not, the left zone shows just the application’s name and the app keeps drawing its own menu bar in its window.

GTK 3/4 apps — usually export automatically over the GTK application-menu D-Bus interfaces.
Qt/KDE apps — need appmenu-qt5 / the AppMenu platform theme plugin.
Electron and browsers — mostly do not export menus.
X11 apps — can export via appmenu-gtk-module and the UNITY_MENUBAR path.

The application name shown comes from the window’s app_id mapped through the desktop entry database.

System tray

The right zone implements StatusNotifierHost, the modern tray standard (org.kde.StatusNotifierItem). Any app that registers an SNI icon appears here: Nextcloud, Telegram, Slack, Steam, KeePassXC, network and volume applets.

Click	Effect
Left	Open the icon’s context menu
Right	Activate — usually raises the app’s window
Middle	Secondary activate (app-defined)

Hovering shows the tooltip the app supplies. Icons are ordered by registration time, newest to the left.

Legacy XEmbed tray icons (the old X11 system tray) are not supported; that standard has no Wayland equivalent. Apps that only do XEmbed will not appear.

Clock

The clock is on the far right. Its format is a chrono strftime string:

# ~/.config/otto/topbar.toml
clock_format = "%B %-d, %A %H:%M"

That default renders as March 23, Thursday 21:16. Some other useful formats:

Format	Renders as
`"%H:%M"`	`21:16`
`"%a %d %b %H:%M"`	`Thu 23 Mar 21:16`
`"%I:%M %p"`	`09:16 PM`
`"%Y-%m-%d %H:%M:%S"`	`2026-03-23 21:16:04`

Configuration

otto-bar has its own config file, loaded from — in order, later overriding earlier:

/etc/otto/topbar.toml
~/.config/otto/topbar.toml
./otto_topbar.toml (development override in the working directory)

clock_format is currently the only option. Bar height, colours and blur follow the compositor’s theme.

Theming

The bar follows the system light/dark setting, read from the XDG Settings portal (org.freedesktop.appearance color-scheme). Change theme_scheme in your Otto config and the bar re-colours within about a second, no restart needed. See Theming.

Multi-monitor

The bar appears on the primary monitor only. A reduced clock-and-tray bar for secondary monitors is designed but not implemented.

Troubleshooting

The bar does not appear. Check it is running (pgrep otto-bar) and that it found the Wayland socket. Run it by hand from a terminal inside the session to see errors.

No menus for any app. DBusMenu is opt-in per toolkit — see Getting an app to export its menu above.

A tray icon is missing. It is probably XEmbed-only. Check whether the app has an SNI or “AppIndicator” option.

The clock format is ignored. A malformed strftime string falls back to the default. Verify the file parses as TOML and the key is at the top level, not in a table.