diff --git a/src/trx-client/src/remote_client.rs b/src/trx-client/src/remote_client.rs
index 19ed3af..0ad0a99 100644
--- a/src/trx-client/src/remote_client.rs
+++ b/src/trx-client/src/remote_client.rs
@@ -12,9 +12,9 @@ use tokio::time::{self, Instant};
 use tracing::{info, warn};
 
 use trx_core::rig::request::RigRequest;
-use trx_core::rig::state::{RigState, SpectrumData};
+use trx_core::rig::state::RigState;
 use trx_core::{RigError, RigResult};
-use trx_frontend::RemoteRigEntry;
+use trx_frontend::{RemoteRigEntry, SharedSpectrum};
 use trx_protocol::rig_command_to_client;
 use trx_protocol::types::RigEntry;
 use trx_protocol::{ClientCommand, ClientEnvelope, ClientResponse};
@@ -49,7 +49,7 @@ pub struct RemoteClientConfig {
     pub known_rigs: Arc<Mutex<Vec<RemoteRigEntry>>>,
     pub poll_interval: Duration,
     /// Shared buffer updated by spectrum polling; None when backend has no spectrum.
-    pub spectrum: Arc<Mutex<Option<SpectrumData>>>,
+    pub spectrum: Arc<Mutex<SharedSpectrum>>,
 }
 
 pub async fn run_remote_client(
@@ -152,13 +152,13 @@ async fn handle_connection(
                 {
                     Ok(snapshot) => {
                         if let Ok(mut guard) = config.spectrum.lock() {
-                            *guard = snapshot.spectrum;
+                            guard.replace(snapshot.spectrum);
                         }
                     }
                     Err(_) => {
                         // Backend may not support spectrum; clear buffer silently.
                         if let Ok(mut guard) = config.spectrum.lock() {
-                            *guard = None;
+                            guard.replace(None);
                         }
                     }
                 }
@@ -674,7 +674,7 @@ mod tests {
                 selected_rig_id: Arc::new(Mutex::new(None)),
                 known_rigs: Arc::new(Mutex::new(Vec::new())),
                 poll_interval: Duration::from_millis(100),
-                spectrum: Arc::new(Mutex::new(None)),
+                spectrum: Arc::new(Mutex::new(SharedSpectrum::default())),
             },
             req_rx,
             state_tx,
@@ -710,7 +710,7 @@ mod tests {
             selected_rig_id: Arc::new(Mutex::new(Some("sdr".to_string()))),
             known_rigs: Arc::new(Mutex::new(Vec::new())),
             poll_interval: Duration::from_millis(500),
-            spectrum: Arc::new(Mutex::new(None)),
+            spectrum: Arc::new(Mutex::new(SharedSpectrum::default())),
         };
         let envelope = super::build_envelope(&config, trx_protocol::ClientCommand::GetState);
         assert_eq!(envelope.token.as_deref(), Some("secret"));
diff --git a/src/trx-client/trx-frontend/src/lib.rs b/src/trx-client/trx-frontend/src/lib.rs
index a22c8a0..1a115c9 100644
--- a/src/trx-client/trx-frontend/src/lib.rs
+++ b/src/trx-client/trx-frontend/src/lib.rs
@@ -36,6 +36,23 @@ pub trait FrontendSpawner {
     ) -> JoinHandle<()>;
 }
 
+#[derive(Debug, Default)]
+pub struct SharedSpectrum {
+    revision: u64,
+    frame: Option<SpectrumData>,
+}
+
+impl SharedSpectrum {
+    pub fn replace(&mut self, frame: Option<SpectrumData>) {
+        self.revision = self.revision.wrapping_add(1);
+        self.frame = frame;
+    }
+
+    pub fn snapshot(&self) -> (u64, Option<SpectrumData>) {
+        (self.revision, self.frame.clone())
+    }
+}
+
 pub type FrontendSpawnFn = fn(
     watch::Receiver<RigState>,
     mpsc::Sender<RigRequest>,
@@ -156,7 +173,7 @@ pub struct FrontendRuntimeContext {
     /// Owner callsign from trx-client config/CLI for frontend display.
     pub owner_callsign: Option<String>,
     /// Latest spectrum frame from the active SDR rig; None for non-SDR backends.
-    pub spectrum: Arc<Mutex<Option<SpectrumData>>>,
+    pub spectrum: Arc<Mutex<SharedSpectrum>>,
 }
 
 impl FrontendRuntimeContext {
@@ -185,7 +202,7 @@ impl FrontendRuntimeContext {
             remote_active_rig_id: Arc::new(Mutex::new(None)),
             remote_rigs: Arc::new(Mutex::new(Vec::new())),
             owner_callsign: None,
-            spectrum: Arc::new(Mutex::new(None)),
+            spectrum: Arc::new(Mutex::new(SharedSpectrum::default())),
         }
     }
 }
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css
index 77afb55..5299976 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css
+++ b/src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css
@@ -27,6 +27,7 @@
   --wavelength-fg: #8da3be;
   --spectrum-bg: #0a0f18;
   --jog-wheel-size: 83.2px;
+  --header-waterfall-overlap: 3.2rem;
 }
 
 [data-theme="light"] {
@@ -378,10 +379,10 @@ small { color: var(--text-muted); }
   grid-template-columns: auto minmax(0, 1fr);
   align-items: center;
   column-gap: 1rem;
-  margin-bottom: -0.45rem;
+  margin-bottom: 0;
   padding: 0.25rem 0 0.15rem;
   position: relative;
-  z-index: 2;
+  z-index: 3;
 }
 .header-text {
   width: auto;
@@ -391,17 +392,20 @@ small { color: var(--text-muted); }
 .title { font-size: 1.4rem; font-weight: 700; display: inline-flex; align-items: center; gap: 0.35rem; }
 .overview-strip {
   width: 100%;
-  margin: 0 0 0.95rem;
-  padding-top: 0.8rem;
+  margin: calc(-1 * var(--header-waterfall-overlap)) 0 0.95rem;
   position: relative;
   z-index: 1;
 }
 .overview-toolbar {
   display: flex;
   align-items: center;
-  justify-content: flex-start;
+  justify-content: flex-end;
   gap: 0.75rem;
-  margin-bottom: 0.25rem;
+  margin-bottom: 0;
+  position: absolute;
+  top: calc(var(--header-waterfall-overlap) + 0.2rem);
+  right: 0.15rem;
+  z-index: 2;
 }
 .overview-label {
   margin-left: auto;
@@ -663,6 +667,7 @@ button:focus-visible, input:focus-visible, select:focus-visible {
   .card { padding: 0.7rem 0.7rem 1rem; }
   button { min-height: 2.8rem; font-size: 0.95rem; }
   input.status-input, select.status-input { font-size: 1.1rem; }
+  :root { --header-waterfall-overlap: 2.2rem; }
   .controls-tray { width: max(100%, 52rem); padding-left: 0.85rem; padding-right: 0.85rem; }
   .freq-inline { gap: 0.5rem; }
   .freq-inline { flex-wrap: wrap; }
@@ -672,7 +677,7 @@ button:focus-visible, input:focus-visible, select:focus-visible {
   .top-bar-actions { width: 100%; justify-content: space-between; }
   .header-rig-switch { width: auto; justify-content: flex-end; }
   .header-rig-switch select { min-width: 6.5rem; }
-  .overview-toolbar { flex-wrap: wrap; }
+  .overview-toolbar { top: calc(var(--header-waterfall-overlap) + 0.15rem); }
   .controls-row { grid-template-columns: 1fr auto; }
   .controls-col-wfm { grid-column: 1 / -1; }
   .controls-col-power { grid-column: 1 / -1; }
diff --git a/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs b/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs
index 14166b1..f761683 100644
--- a/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs
+++ b/src/trx-client/trx-frontend/trx-frontend-http/src/api.rs
@@ -299,28 +299,33 @@ pub async fn spectrum(
     context: web::Data<Arc<FrontendRuntimeContext>>,
 ) -> Result<HttpResponse, Error> {
     let context_updates = context.get_ref().clone();
-    let mut last_json: Option<String> = None;
+    let mut last_revision: Option<u64> = None;
     let updates =
         IntervalStream::new(time::interval(Duration::from_millis(200))).filter_map(move |_| {
             let context = context_updates.clone();
             std::future::ready({
-                let next_json = context
+                let next = context
                     .spectrum
                     .lock()
                     .ok()
-                    .and_then(|g| g.as_ref().and_then(|s| serde_json::to_string(s).ok()));
+                    .map(|g| g.snapshot());
 
-                let payload = match (last_json.as_ref(), next_json) {
-                    (Some(prev), Some(next)) if prev == &next => None,
-                    (_, Some(next)) => {
-                        last_json = Some(next.clone());
-                        Some(next)
+                let payload = match next {
+                    Some((revision, frame)) if last_revision == Some(revision) => None,
+                    Some((revision, Some(frame))) => {
+                        last_revision = Some(revision);
+                        serde_json::to_string(&frame).ok()
                     }
-                    (Some(_), None) => {
-                        last_json = None;
+                    Some((revision, None)) => {
+                        last_revision = Some(revision);
                         Some("null".to_string())
                     }
-                    (None, None) => None,
+                    None if last_revision.is_some() => {
+                        // Lock poisoning is transient; retry instead of breaking stream semantics.
+                        last_revision = None;
+                        Some("null".to_string())
+                    }
+                    None => None,
                 };
 
                 payload.map(|json| Ok::<Bytes, Error>(Bytes::from(format!("data: {json}\n\n"))))