fix: wallpaper-only windows on secondary monitors (v0.8.5)

The v0.8.4 keyboard fix only half-worked: keys were still dropped
until the pointer moved to the built-in panel. Niri scopes layer-shell
keyboard routing per active output, so a single Exclusive surface is
not enough when another output is active.

Revert 2026-04-08 partially: only the built-in panel shows the login
widget, other monitors get a wallpaper-only window with
KeyboardMode::None. Hotplugged monitors also get wallpaper-only.
Compositor-agnostic — no Niri IPC.

CLAUDE.md

@@ -44,8 +44,8 @@ cd pkg && makepkg -sf && sudo pacman -U moongreet-git-<version>-x86_64.pkg.tar.z
 - `i18n.rs` — Locale-Erkennung (LANG / /etc/locale.conf) und String-Tabellen (DE/EN), alle UI- und Login-Fehlermeldungen
 - `fingerprint.rs` — fprintd D-Bus Probe (gio::DBusProxy) — Geräteerkennung und Enrollment-Check für UI-Feedback
 - `config.rs` — TOML-Config ([appearance] background, gtk-theme, fingerprint-enabled) + Wallpaper-Fallback + Blur-Validierung (finite, clamp 0–200)
-- `greeter.rs` — GTK4 UI (Overlay-Layout), Login-Flow via greetd IPC (Multi-Stage-Auth für fprintd), Faillock-Warnung, Avatar-Cache, Last-User/Last-Session Persistence (0o700 Dirs, 0o600 Files)
-- `main.rs` — Entry Point, GTK App, Layer Shell Setup, Multi-Monitor mit Hotplug via `items-changed` auf Monitor-ListModel (one greeter window per monitor; keyboard goes to the built-in display via `pick_primary_monitor_index`, falls back to first), systemd-journal-logger
+- `greeter.rs` — GTK4 UI (Overlay-Layout), Login-Flow via greetd IPC (Multi-Stage-Auth für fprintd), Faillock-Warnung, Avatar-Cache, Last-User/Last-Session Persistence (0o700 Dirs, 0o600 Files). Zweite Funktion `create_wallpaper_window()` für Sekundär-Monitore (Background only, keine Widgets)
+- `main.rs` — Entry Point, GTK App, Layer Shell Setup, Multi-Monitor mit Hotplug via `items-changed` auf Monitor-ListModel. Built-in display (via `pick_primary_monitor_index`) zeigt das Login-Widget mit `KeyboardMode::Exclusive`, alle anderen Monitore (inkl. Hotplug) zeigen nur Wallpaper mit `KeyboardMode::None`. Systemd-journal-logger.
 - `resources/style.css` — Catppuccin-inspiriertes Theme
 
 ## Design Decisions
@@ -66,3 +66,4 @@ cd pkg && makepkg -sf && sudo pacman -U moongreet-git-<version>-x86_64.pkg.tar.z
 - **Shared Wallpaper Texture**: `gdk::Texture` wird einmal in `load_background_texture()` dekodiert und per Ref-Count an alle Fenster geteilt — vermeidet redundante JPEG-Dekodierung pro Monitor
 - **Wallpaper-Validierung**: GResource-Zweig via `resources_lookup_data()` + `from_bytes()` (kein Abort bei fehlendem Pfad), Dateigröße-Limit 50 MB, non-UTF-8-Pfade → `None`
 - **Error-Detail-Filterung**: GDK/greetd-Fehlerdetails nur auf `debug!`-Level, `warn!` ohne interne Details — verhindert Systeminfo-Leak ins Journal
+- **Single Greeter UI, Wallpaper auf Sekundären**: Login-Widget nur auf dem Built-in-Panel, andere Monitore bekommen `create_wallpaper_window()` mit `KeyboardMode::None`. Grund: Niri (und andere Compositor) scopen Layer-Shell Keyboard-Routing per Output — ein einziges Exclusive-Surface auf dem "falschen" Output verhindert nicht, dass Keys woanders versanden. Compositor-agnostisch, kein Niri-IPC.

Cargo.lock

@@ -575,7 +575,7 @@ dependencies = [
 
 [[package]]
 name = "moongreet"
-version = "0.8.4"
+version = "0.8.5"
 dependencies = [
  "gdk-pixbuf",
  "gdk4",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moongreet"
-version = "0.8.4"
+version = "0.8.5"
 edition = "2024"
 description = "A greetd greeter for Wayland with GTK4 and Layer Shell"
 license = "MIT"

DECISIONS.md

@@ -1,5 +1,12 @@
 # Decisions
 
+## 2026-04-23 – Wallpaper-only windows on secondary monitors (v0.8.5)
+
+- **Who**: ClaudeCode, Dom
+- **Why**: The v0.8.4 fix (keyboard grab on the built-in panel) only half-worked. The greeter still rejected keystrokes until the user moved the mouse to eDP-1 — Niri scopes layer-shell keyboard routing by active output, so even though the primary window was the sole `KeyboardMode::Exclusive` surface, keys went nowhere when another output was active. Hardcoding a compositor focus call (e.g. `niri msg action focus-monitor`) would tie moongreet to a specific compositor.
+- **Tradeoffs**: Reverts part of 2026-04-08: only the built-in panel shows the full greeter UI, other monitors go back to wallpaper-only. Users with multiple monitors lose the symmetric "login widget on every screen" look, but gain a reliable keyboard path regardless of which output the compositor considers active at startup. Compositor-agnostic — no Niri-specific IPC.
+- **How**: New `create_wallpaper_window()` in `greeter.rs` builds a minimal `ApplicationWindow` with the shared background `Picture` (same `blur_cache` as the primary) and no login widgets. `main.rs` uses `create_greeter_window()` for the index returned by `pick_primary_monitor_index()` and `create_wallpaper_window()` for the rest. Hotplugged monitors also get wallpaper-only windows. Both variants use `Layer::Top`; only the primary sets `KeyboardMode::Exclusive`.
+
 ## 2026-04-23 – Keyboard focus on built-in display, not first enumerated monitor (v0.8.4)
 
 - **Who**: ClaudeCode, Dom

README.md

@@ -12,7 +12,7 @@ Part of the Moonarch ecosystem.
 - **Last user/session** — Remembered in `/var/cache/moongreet/`
 - **Power actions** — Reboot / Shutdown via `loginctl`
 - **Layer Shell** — Fullscreen via gtk4-layer-shell (TOP layer)
-- **Multi-monitor + hotplug** — Full greeter UI on all monitors (keyboard input on first), hotplugged monitors get windows automatically
+- **Multi-monitor + hotplug** — Login UI on the built-in display, wallpaper-only on other monitors; hotplugged monitors get wallpaper windows automatically
 - **GPU blur** — Background blur via GskBlurNode (shared cache across monitors)
 - **i18n** — German and English (auto-detected from system locale)
 - **Faillock warning** — Warns after 2 failed attempts, locked message after 3

src/greeter.rs

@@ -219,6 +219,31 @@ fn create_background_picture(
     background
 }
 
+/// Create a wallpaper-only window for secondary monitors.
+///
+/// Shows the same background (and shared blurred texture via `blur_cache`) as
+/// the primary greeter window, but carries no login widgets. Paired with
+/// `KeyboardMode::None` at the layer-shell level so the compositor never
+/// routes input here — preventing focus from landing on a secondary output.
+pub fn create_wallpaper_window(
+    texture: Option<&gdk::Texture>,
+    config: &Config,
+    blur_cache: &Rc<RefCell<Option<gdk::Texture>>>,
+    app: &gtk::Application,
+) -> gtk::ApplicationWindow {
+    let window = gtk::ApplicationWindow::builder()
+        .application(app)
+        .build();
+    window.add_css_class("greeter");
+    window.set_default_size(1920, 1080);
+
+    if let Some(texture) = texture {
+        window.set_child(Some(&create_background_picture(texture, config.background_blur, blur_cache)));
+    }
+
+    window
+}
+
 /// Shared mutable state for the greeter UI.
 struct GreeterState {
     selected_user: Option<User>,

src/main.rs

@@ -113,15 +113,20 @@ fn activate(app: &gtk::Application) {
                 .item(i)
                 .and_then(|obj| obj.downcast::<gdk::Monitor>().ok())
             {
-                let window = greeter::create_greeter_window(bg_texture.as_ref(), &config, &blur_cache, app);
-                setup_layer_shell(&window, i as usize == primary_idx, gtk4_layer_shell::Layer::Top);
+                let is_primary = i as usize == primary_idx;
+                let window = if is_primary {
+                    greeter::create_greeter_window(bg_texture.as_ref(), &config, &blur_cache, app)
+                } else {
+                    greeter::create_wallpaper_window(bg_texture.as_ref(), &config, &blur_cache, app)
+                };
+                setup_layer_shell(&window, is_primary, gtk4_layer_shell::Layer::Top);
                 window.set_monitor(Some(&monitor));
                 window.present();
             }
         }
 
-        // Handle monitor hotplug — create greeter windows for newly added monitors
-        // (without keyboard, since the primary monitor already has it)
+        // Handle monitor hotplug — hotplugged monitors get wallpaper-only
+        // windows so keyboard focus never migrates off the primary.
         let bg_texture = Rc::new(bg_texture);
         let config = Rc::new(config);
         monitors.connect_items_changed(clone!(
@@ -135,8 +140,8 @@ fn activate(app: &gtk::Application) {
                         .item(i)
                         .and_then(|obj| obj.downcast::<gdk::Monitor>().ok())
                     {
-                        log::debug!("Monitor hotplug: creating greeter window");
-                        let window = greeter::create_greeter_window(
+                        log::debug!("Monitor hotplug: creating wallpaper window");
+                        let window = greeter::create_wallpaper_window(
                             bg_texture.as_ref().as_ref(), &config, &blur_cache, &app,
                         );
                         setup_layer_shell(&window, false, gtk4_layer_shell::Layer::Top);