diff --git a/frontend/src/components/social/chat/Message.tsx b/frontend/src/components/social/chat/Message.tsx
index 552ab84..6067746 100644
--- a/frontend/src/components/social/chat/Message.tsx
+++ b/frontend/src/components/social/chat/Message.tsx
@@ -12,6 +12,8 @@ import { canDeleteMessage } from "@/hooks/usePermissions";
 import { formatRelative } from "@/utils/relativeTime";
 import { apiSocialMessagesDestroy } from "@/api/generated/private/chat/chat";
 
+type MemberInfo = { id: number; username: string; avatar: string | null };
+
 interface Props {
   message: MessageModel;
   chat: Chat | null;
@@ -59,13 +61,26 @@ export default function Message({ message, chat, onReply, onReact, highlighted,
   const hasMedia = (message.media_files?.length ?? 0) > 0;
   const hasText = !!message.content;
 
-  // Group reactions by emoji { "👍": { count, mine } }
-  const reactionGroups = (message.reactions ?? []).reduce<Record<string, { count: number; mine: boolean }>>(
+  // Build a username/avatar lookup from the chat member list (members_detail is
+  // returned by the API but not yet in the generated type, so we cast).
+  const membersMap = (
+    (chat as unknown as { members_detail?: MemberInfo[] })?.members_detail ?? []
+  ).reduce<Record<number, MemberInfo>>((acc, m) => { acc[m.id] = m; return acc; }, {});
+  if (user != null) {
+    membersMap[user.id] ??= { id: user.id, username: user.username, avatar: user.avatar ?? null };
+  }
+
+  // Group reactions by emoji { "👍": { count, mine, reactors } }
+  const reactionGroups = (message.reactions ?? []).reduce<
+    Record<string, { count: number; mine: boolean; reactors: MemberInfo[] }>
+  >(
     (acc, r) => {
       const emoji = r.emoji;
-      if (!acc[emoji]) acc[emoji] = { count: 0, mine: false };
+      const userId = r.user as unknown as number;
+      if (!acc[emoji]) acc[emoji] = { count: 0, mine: false, reactors: [] };
       acc[emoji].count++;
-      if ((r.user as unknown as number) === user?.id) acc[emoji].mine = true;
+      if (userId === user?.id) acc[emoji].mine = true;
+      acc[emoji].reactors.push(membersMap[userId] ?? { id: userId, username: `User ${userId}`, avatar: null });
       return acc;
     },
     {},
@@ -228,23 +243,161 @@ export default function Message({ message, chat, onReply, onReact, highlighted,
           ].join(" ")}
         >
           {Object.entries(reactionGroups).map(([emoji, { count, mine }]) => (
-            <button
+            <ReactionPill
               key={emoji}
-              type="button"
-              onClick={() => onReact?.(message, emoji)}
-              className={[
-                "flex items-center gap-1 rounded-full px-2 py-0.5 text-xs transition-colors",
-                mine
-                  ? "bg-brand-accent/20 border border-brand-accent/50 text-brand-accent"
-                  : "bg-brand-bgLight/60 border border-transparent hover:border-brand-lines/30 text-brand-text/80",
-              ].join(" ")}
-            >
-              <span>{emoji}</span>
-              {count > 1 && <span>{count}</span>}
-            </button>
+              emoji={emoji}
+              count={count}
+              mine={mine}
+              allGroups={reactionGroups}
+              currentUserId={user?.id}
+              isOwn={isOwn}
+              onRemove={(ej) => onReact?.(message, ej)}
+            />
           ))}
         </div>
       )}
     </div>
   );
 }
+
+// ---------------------------------------------------------------------------
+// ReactionPill — self-contained pill + tabbed who-reacted popover
+// ---------------------------------------------------------------------------
+
+type AllReactor = MemberInfo & { reactionEmoji: string };
+
+interface ReactionPillProps {
+  emoji: string;
+  count: number;
+  mine: boolean;
+  allGroups: Record<string, { count: number; mine: boolean; reactors: MemberInfo[] }>;
+  currentUserId?: number;
+  isOwn: boolean;
+  onRemove: (emoji: string) => void;
+}
+
+function ReactionPill({ emoji, count, mine, allGroups, currentUserId, isOwn, onRemove }: ReactionPillProps) {
+  const [open, setOpen] = useState(false);
+  const [activeTab, setActiveTab] = useState<string>("all");
+  const wrapperRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    function handleOutside(e: MouseEvent) {
+      if (wrapperRef.current && !wrapperRef.current.contains(e.target as Node)) {
+        setOpen(false);
+      }
+    }
+    document.addEventListener("mousedown", handleOutside);
+    return () => document.removeEventListener("mousedown", handleOutside);
+  }, [open]);
+
+  function handleToggle() {
+    if (!open) {
+      setActiveTab(emoji);
+      setOpen(true);
+    } else {
+      setOpen(false);
+    }
+  }
+
+  const emojiTabs = Object.keys(allGroups);
+
+  const allReactors: AllReactor[] = emojiTabs.flatMap((ej) =>
+    allGroups[ej].reactors.map((r) => ({ ...r, reactionEmoji: ej })),
+  );
+
+  const displayReactors: AllReactor[] =
+    activeTab === "all"
+      ? allReactors
+      : (allGroups[activeTab]?.reactors ?? []).map((r) => ({ ...r, reactionEmoji: activeTab }));
+
+  return (
+    <div ref={wrapperRef} className="relative">
+      {open && (
+        <div
+          className={[
+            "absolute bottom-full mb-1.5 z-30 w-72 rounded-2xl border border-brand-lines/20 bg-brand-bgLight shadow-2xl",
+            isOwn ? "right-0" : "left-0",
+          ].join(" ")}
+        >
+          {/* Tab bar */}
+          <div className="flex items-center gap-0.5 overflow-x-auto border-b border-brand-lines/15 px-3 pt-2.5 pb-2 scrollbar-none">
+            <button
+              type="button"
+              onClick={() => setActiveTab("all")}
+              className={[
+                "shrink-0 rounded-lg px-2.5 py-1 text-xs font-medium transition-colors",
+                activeTab === "all"
+                  ? "bg-brand-accent/20 text-brand-accent"
+                  : "text-brand-text/50 hover:bg-brand-lines/10 hover:text-brand-text/80",
+              ].join(" ")}
+            >
+              Vše <span className="opacity-60">{allReactors.length}</span>
+            </button>
+            {emojiTabs.map((ej) => (
+              <button
+                key={ej}
+                type="button"
+                onClick={() => setActiveTab(ej)}
+                className={[
+                  "flex shrink-0 items-center gap-1 rounded-lg px-2.5 py-1 text-xs transition-colors",
+                  activeTab === ej
+                    ? "bg-brand-accent/20 text-brand-accent"
+                    : "text-brand-text/50 hover:bg-brand-lines/10 hover:text-brand-text/80",
+                ].join(" ")}
+              >
+                <span>{ej}</span>
+                <span className="opacity-60">{allGroups[ej].count}</span>
+              </button>
+            ))}
+          </div>
+
+          {/* Reactor list */}
+          <ul className="max-h-56 overflow-y-auto py-1.5">
+            {displayReactors.map((r) => {
+              const isMe = r.id === currentUserId;
+              return (
+                <li key={`${r.id}-${r.reactionEmoji}`}>
+                  {isMe ? (
+                    <button
+                      type="button"
+                      onClick={() => { onRemove(r.reactionEmoji); setOpen(false); }}
+                      className="flex w-full flex-col px-4 py-2.5 text-left transition-colors hover:bg-brand-lines/10"
+                    >
+                      <div className="flex items-center gap-3">
+                        <Avatar name={r.username} src={r.avatar} size={24} />
+                        <span className="flex-1 text-sm font-medium text-brand-text">{r.username}</span>
+                        {activeTab === "all" && <span className="text-base leading-none">{r.reactionEmoji}</span>}
+                      </div>
+                      <span className="mt-1 pl-[36px] text-[10px] text-brand-text/40">Klikni pro odebrání reakce</span>
+                    </button>
+                  ) : (
+                    <div className="flex items-center gap-3 px-4 py-2.5">
+                      <Avatar name={r.username} src={r.avatar} size={24} />
+                      <span className="flex-1 text-sm text-brand-text/80">{r.username}</span>
+                      {activeTab === "all" && <span className="text-base leading-none">{r.reactionEmoji}</span>}
+                    </div>
+                  )}
+                </li>
+              );
+            })}
+          </ul>
+        </div>
+      )}
+      <button
+        type="button"
+        onClick={handleToggle}
+        className={[
+          "flex items-center gap-1 rounded-full px-2 py-0.5 text-xs transition-colors",
+          mine
+            ? "bg-brand-accent/20 border border-brand-accent/50 text-brand-accent"
+            : "bg-brand-bgLight/60 border border-transparent hover:border-brand-lines/30 text-brand-text/80",
+        ].join(" ")}
+      >
+        <span>{emoji}</span>
+        {count > 1 && <span>{count}</span>}
+      </button>
+    </div>
+  );
+}
diff --git a/frontend/src/hooks/useChatSocket.ts b/frontend/src/hooks/useChatSocket.ts
index bfeb8a0..dc6e68b 100644
--- a/frontend/src/hooks/useChatSocket.ts
+++ b/frontend/src/hooks/useChatSocket.ts
@@ -36,6 +36,9 @@ export function useChatSocket({ chatId, onEvent }: Opts) {
   useEffect(() => {
     if (chatId == null || !Number.isFinite(chatId)) return;
     closedByUserRef.current = false;
+    // Guards against React StrictMode double-invoke: events from the first
+    // (torn-down) WebSocket are silently dropped after cleanup runs.
+    let mounted = true;
 
     let reconnectTimer: number | undefined;
 
@@ -45,11 +48,13 @@ export function useChatSocket({ chatId, onEvent }: Opts) {
       wsRef.current = ws;
 
       ws.addEventListener("open", () => {
+        if (!mounted) return;
         setStatus("open");
         reconnectAttemptRef.current = 0;
       });
 
       ws.addEventListener("message", (e) => {
+        if (!mounted) return;
         try {
           const data = JSON.parse(e.data) as ChatSocketEvent;
           setLastEvent(data);
@@ -59,9 +64,10 @@ export function useChatSocket({ chatId, onEvent }: Opts) {
         }
       });
 
-      ws.addEventListener("error", () => setStatus("error"));
+      ws.addEventListener("error", () => { if (mounted) setStatus("error"); });
 
       ws.addEventListener("close", () => {
+        if (!mounted) return;
         setStatus("closed");
         if (closedByUserRef.current) return;
         const attempt = reconnectAttemptRef.current++;
@@ -73,6 +79,7 @@ export function useChatSocket({ chatId, onEvent }: Opts) {
     connect();
 
     return () => {
+      mounted = false;
       closedByUserRef.current = true;
       if (reconnectTimer) window.clearTimeout(reconnectTimer);
       wsRef.current?.close();
diff --git a/frontend/src/pages/social/chat/ChatRoomPage.tsx b/frontend/src/pages/social/chat/ChatRoomPage.tsx
index 14dcb65..0564dd6 100644
--- a/frontend/src/pages/social/chat/ChatRoomPage.tsx
+++ b/frontend/src/pages/social/chat/ChatRoomPage.tsx
@@ -198,7 +198,12 @@ export default function ChatRoomPage() {
                 if (m.id !== event.message_id) return m;
                 let reactions = [...(m.reactions ?? [])] as typeof m.reactions;
                 if (event.action === "added") {
-                  reactions = [...reactions, { id: -Date.now(), user: event.user_id, emoji: event.emoji, created_at: new Date().toISOString() } as never];
+                  const alreadyExists = reactions.some(
+                    (r) => (r.user as unknown as number) === event.user_id && r.emoji === event.emoji,
+                  );
+                  if (!alreadyExists) {
+                    reactions = [...reactions, { id: -Date.now(), user: event.user_id, emoji: event.emoji, created_at: new Date().toISOString() } as never];
+                  }
                 } else if (event.action === "removed") {
                   reactions = reactions.filter((r) => !((r.user as unknown as number) === event.user_id && r.emoji === event.emoji));
                 } else if (event.action === "switched") {