diff --git a/data/defaults.json b/data/defaults.json
index 6afdaa1..718f8d1 100644
--- a/data/defaults.json
+++ b/data/defaults.json
@@ -1,5 +1,5 @@
 {
-  "deployments_base": "/sls/mx/applications/aaredaq",
+  "deployments_base": "/sls/mx/applications/AareDAQ",
   "default_venv_name": ".venv",
   "default_gui_file": "src/aare/gui/gui.py",
   "default_server_file": "src/aare/daq/server.py",
diff --git a/src/config.rs b/src/config.rs
index a8a83ab..fb488ea 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -192,4 +192,53 @@ mod tests {
             "expected field path in error, got: {message}"
         );
     }
+
+    #[test]
+    fn join_relative_keeps_relative_paths() {
+        assert_eq!(
+            join_relative(Path::new("/base"), Path::new("sub/x.py")),
+            PathBuf::from("/base/sub/x.py")
+        );
+    }
+
+    #[test]
+    fn join_relative_strips_leading_slash() {
+        assert_eq!(
+            join_relative(Path::new("/base"), Path::new("/sub/x.py")),
+            PathBuf::from("/base/sub/x.py")
+        );
+    }
+
+    #[test]
+    fn absolute_entry_points_resolve_relative_to_dir() {
+        // A leading slash on an entry point is treated as relative to `dir`,
+        // not as an absolute path.
+        let json = r#"{
+            "deployments_base": "/apps",
+            "default_venv_name": ".venv",
+            "default_gui_file": "src/gui.py",
+            "default_server_file": "src/server.py",
+            "map": { "x10sa": { "dir": "d", "gui_file": "/abs/gui.py" } }
+        }"#;
+
+        let config = load_config(json).unwrap();
+        assert_eq!(
+            config.entries["x10sa"].gui_file,
+            PathBuf::from("/apps/d/abs/gui.py")
+        );
+    }
+
+    #[test]
+    fn custom_venv_overrides_default() {
+        let config = load_config(SAMPLE).unwrap();
+        // x10sa sets "venv": "pxii"; x06da falls back to ".venv".
+        assert_eq!(
+            config.entries["x10sa"].python,
+            PathBuf::from("/apps/aaredaq-pxii/pxii/bin/python")
+        );
+        assert_eq!(
+            config.entries["x06da"].python,
+            PathBuf::from("/apps/aaredaq-pxiii/.venv/bin/python")
+        );
+    }
 }
diff --git a/src/main.rs b/src/main.rs
index 7bb350d..d345401 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -10,17 +10,37 @@ use clap::{Parser, Subcommand};
 use config::{Config, LauncherEntry, load_config};
 use detect::detect_beamline;
 
+/// Config file installed by the RPM, preferred when it exists.
+const INSTALLED_CONFIG: &str = "/etc/aarel/defaults.json";
+/// Config file shipped in the source tree, used as a fallback.
+const LOCAL_CONFIG: &str = "data/defaults.json";
+
 #[derive(Parser)]
 #[command(name = "aarel")]
 struct Cli {
-    /// Path to the launcher config file.
-    #[arg(long, default_value = "data/defaults.json")]
-    config: PathBuf,
+    /// Path to the launcher config file. Defaults to /etc/aarel/defaults.json,
+    /// falling back to ./data/defaults.json.
+    #[arg(long)]
+    config: Option<PathBuf>,
 
     #[command(subcommand)]
     command: Command,
 }
 
+/// Resolve the config path: the explicit `--config`, else the installed config
+/// if present, else the local one.
+fn resolve_config_path(config: Option<PathBuf>) -> PathBuf {
+    if let Some(path) = config {
+        return path;
+    }
+    let installed = PathBuf::from(INSTALLED_CONFIG);
+    if installed.is_file() {
+        installed
+    } else {
+        PathBuf::from(LOCAL_CONFIG)
+    }
+}
+
 #[derive(Subcommand)]
 enum Command {
     /// Enter the TUI to choose what to launch
@@ -45,12 +65,13 @@ enum Command {
 fn main() -> Result<()> {
     let cli = Cli::parse();
 
-    let json = std::fs::read_to_string(&cli.config)
-        .with_context(|| format!("failed to read config file {}", cli.config.display()))?;
+    let config_path = resolve_config_path(cli.config);
+    let json = std::fs::read_to_string(&config_path)
+        .with_context(|| format!("failed to read config file {}", config_path.display()))?;
     let config = load_config(&json)?;
 
-    check_base_exists("deployments_base", &config.deployments_base, &cli.config)?;
-    check_base_exists("venvs_base", &config.deployments_base, &cli.config)?;
+    check_base_exists("deployments_base", &config.deployments_base, &config_path)?;
+    check_base_exists("venvs_base", &config.deployments_base, &config_path)?;
 
     match cli.command {
         Command::Pick => {
diff --git a/src/tui/custom.rs b/src/tui/custom.rs
index 29d35b3..c50e8f2 100644
--- a/src/tui/custom.rs
+++ b/src/tui/custom.rs
@@ -155,3 +155,54 @@ fn dir_list<'a>(title: &'a str, items: &'a [String], focused: bool) -> List<'a>
         .highlight_style(Style::default().add_modifier(Modifier::BOLD | Modifier::REVERSED))
         .highlight_symbol("> ")
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn items(n: usize) -> Vec<String> {
+        (0..n).map(|i| i.to_string()).collect()
+    }
+
+    #[test]
+    fn initial_state_selects_first_when_nonempty() {
+        assert_eq!(initial_state(&items(3)).selected(), Some(0));
+    }
+
+    #[test]
+    fn initial_state_selects_nothing_when_empty() {
+        assert_eq!(initial_state(&items(0)).selected(), None);
+    }
+
+    #[test]
+    fn select_relative_moves_within_bounds() {
+        let items = items(3);
+        let mut state = initial_state(&items);
+        select_relative(&items, &mut state, 1);
+        assert_eq!(state.selected(), Some(1));
+    }
+
+    #[test]
+    fn select_relative_wraps_forward_past_end() {
+        let items = items(3);
+        let mut state = ListState::default();
+        state.select(Some(2));
+        select_relative(&items, &mut state, 1);
+        assert_eq!(state.selected(), Some(0));
+    }
+
+    #[test]
+    fn select_relative_wraps_backward_past_start() {
+        let items = items(3);
+        let mut state = initial_state(&items);
+        select_relative(&items, &mut state, -1);
+        assert_eq!(state.selected(), Some(2));
+    }
+
+    #[test]
+    fn select_relative_on_empty_is_noop() {
+        let mut state = ListState::default();
+        select_relative(&items(0), &mut state, 1);
+        assert_eq!(state.selected(), None);
+    }
+}