diff --git a/shared/components/rstack-collab-overlay.ts b/shared/components/rstack-collab-overlay.ts
index d663e5c..859815e 100644
--- a/shared/components/rstack-collab-overlay.ts
+++ b/shared/components/rstack-collab-overlay.ts
@@ -485,6 +485,19 @@ export class RStackCollabOverlay extends HTMLElement {
 		}
 	}
 
+	/** Deduplicate peers by username, keeping the most recently seen entry per user. */
+	#uniquePeers(): PeerState[] {
+		const byName = new Map<string, PeerState>();
+		for (const peer of this.#peers.values()) {
+			const key = peer.username.toLowerCase();
+			const existing = byName.get(key);
+			if (!existing || peer.lastSeen > existing.lastSeen) {
+				byName.set(key, peer);
+			}
+		}
+		return Array.from(byName.values());
+	}
+
 	// ── Color assignment ──
 
 	#colorForPeer(peerId: string): string {
@@ -536,7 +549,8 @@ export class RStackCollabOverlay extends HTMLElement {
 		const countEl = this.#shadow.getElementById('panel-count');
 		if (!list) return;
 
-		const onlineCount = this.#peers.size + 1;
+		const uniquePeers = this.#uniquePeers();
+		const onlineCount = uniquePeers.length + 1;
 		if (countEl) countEl.textContent = this.#connState === 'connected' ? `${onlineCount} online` : '\u2014';
 
 		const fragments: string[] = [];
@@ -566,9 +580,9 @@ export class RStackCollabOverlay extends HTMLElement {
 			</div>
 		`);
 
-		// Remote peer rows
+		// Remote peer rows (deduplicated by username)
 		const isCanvas = this.#moduleId === 'rspace';
-		for (const [pid, peer] of this.#peers) {
+		for (const peer of uniquePeers) {
 			const ctxParts: string[] = [];
 			if (peer.module) ctxParts.push(peer.module);
 			if (peer.context) ctxParts.push(peer.context);
@@ -580,15 +594,15 @@ export class RStackCollabOverlay extends HTMLElement {
 						<span class="name">${this.#escHtml(peer.username)}</span>
 						${ctxStr ? `<span class="peer-context">${this.#escHtml(ctxStr)}</span>` : ''}
 					</div>
-					${isCanvas ? `<button class="actions-btn" data-pid="${this.#escHtml(pid)}">&gt;</button>` : ''}
+					${isCanvas ? `<button class="actions-btn" data-pid="${this.#escHtml(peer.peerId)}">&gt;</button>` : ''}
 				</div>
 			`);
 			// Expanded actions for canvas
-			if (isCanvas && this.#openActionsId === pid) {
+			if (isCanvas && this.#openActionsId === peer.peerId) {
 				fragments.push(`
 					<div class="people-actions">
-						<button data-action="navigate" data-pid="${this.#escHtml(pid)}">Navigate to</button>
-						<button data-action="ping" data-pid="${this.#escHtml(pid)}">Ping to join you</button>
+						<button data-action="navigate" data-pid="${this.#escHtml(peer.peerId)}">Navigate to</button>
+						<button data-action="ping" data-pid="${this.#escHtml(peer.peerId)}">Ping to join you</button>
 					</div>
 				`);
 			}
@@ -707,9 +721,10 @@ export class RStackCollabOverlay extends HTMLElement {
 			return;
 		}
 
-		const count = this.#peers.size + 1; // +1 for self
+		const uniquePeers = this.#uniquePeers();
+		const count = uniquePeers.length + 1; // +1 for self
 
-		const dots = Array.from(this.#peers.values())
+		const dots = uniquePeers
 			.slice(0, 5) // show max 5 dots
 			.map(p => `<span class="dot" style="background:${p.color}"></span>`)
 			.join('');