diff --git a/CHANGES.md b/CHANGES.md
index 8df4c93f9c..1d13e74f47 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -138,6 +138,7 @@
 - Fix standalone tokens ordering separated from token groups [#9733](https://github.com/penpot/penpot/issues/9733) (PR: [#9736](https://github.com/penpot/penpot/pull/9736))
 - Fix delete invitation modal readability in light theme [#9737](https://github.com/penpot/penpot/issues/9737) (PR: [#9747](https://github.com/penpot/penpot/pull/9747))
 - Fix team invitation not automatically accepted after account validation [#9776](https://github.com/penpot/penpot/issues/9776) (PR: [#9782](https://github.com/penpot/penpot/pull/9782))
+- Fix design tokens vanishing from the sidebar when a token name collides with a token-group prefix from another active set (e.g. `a` in one set and `a.b` in another); the colliding token is now kept and rendered as a broken pill [Github #9584](https://github.com/penpot/penpot/issues/9584)
 
 
 ## 2.15.4
diff --git a/frontend/src/app/main/data/style_dictionary.cljs b/frontend/src/app/main/data/style_dictionary.cljs
index 48320fd9a0..4e0a1fc635 100644
--- a/frontend/src/app/main/data/style_dictionary.cljs
+++ b/frontend/src/app/main/data/style_dictionary.cljs
@@ -553,10 +553,36 @@
 (defn sd-token-uuid [^js sd-token]
   (uuid (.-uuid (.. sd-token -original -id))))
 
+(defn- merge-name-collisions
+  "Re-attach tokens that `ctob/tokens-tree` / `backtrace-tokens-tree`
+  dropped because one token's name is a strict prefix of another's
+  (e.g. `a` vs `a.b` coming from two active sets). `assoc-in` in the
+  tree builder collapses such pairs, so StyleDictionary only sees one
+  of them and the other vanishes from the resolved map — and from the
+  sidebar, even though it still lives in the library (#9584).
+
+  We tag each dropped token with `:error.token/name-collision` so the
+  existing token-pill error rendering picks them up as broken pills,
+  matching the expected behaviour in the issue. Resolved tokens are
+  left untouched."
+  [tokens resolved]
+  (let [resolved-names (set (keys resolved))
+        dropped        (->> tokens
+                            (remove (fn [[k _]] (contains? resolved-names k)))
+                            (map (fn [[k token]]
+                                   [k (assoc token
+                                             :errors
+                                             [(wte/error-with-value
+                                               :error.token/name-collision
+                                               (:name token))])]))
+                            (into {}))]
+    (merge resolved dropped)))
+
 (defn resolve-tokens
   [tokens]
   (let [tokens-tree (ctob/tokens-tree tokens)]
-    (resolve-tokens-tree tokens-tree #(get tokens (sd-token-name %)))))
+    (->> (resolve-tokens-tree tokens-tree #(get tokens (sd-token-name %)))
+         (rx/map #(merge-name-collisions tokens %)))))
 
 (defn resolve-tokens-interactive
   "Interactive check of resolving tokens.
@@ -579,7 +605,8 @@
   same :name path by just looking up that :id in the ids map."
   [tokens]
   (let [{:keys [tokens-tree ids]} (ctob/backtrace-tokens-tree tokens)]
-    (resolve-tokens-tree tokens-tree  #(get ids (sd-token-uuid %)))))
+    (->> (resolve-tokens-tree tokens-tree  #(get ids (sd-token-uuid %)))
+         (rx/map #(merge-name-collisions tokens %)))))
 
 (defn resolve-tokens-with-verbose-errors [tokens]
   (resolve-tokens-tree
diff --git a/frontend/src/app/main/data/workspace/tokens/errors.cljs b/frontend/src/app/main/data/workspace/tokens/errors.cljs
index 0e7a78de9b..4aaae14eba 100644
--- a/frontend/src/app/main/data/workspace/tokens/errors.cljs
+++ b/frontend/src/app/main/data/workspace/tokens/errors.cljs
@@ -52,6 +52,16 @@
    {:error/code :error.token/number-too-large
     :error/fn #(str (tr "errors.tokens.number-too-large" %))}
 
+   ;; Surfaced when a token name conflicts with a token-group prefix
+   ;; across the active sets (e.g. one set defines `a`, another set
+   ;; defines `a.b`). DTCG/StyleDictionary cannot represent both as
+   ;; resolvable leaves, so the colliding token is preserved with this
+   ;; error rather than silently disappearing from the sidebar — see
+   ;; #9584.
+   :error.token/name-collision
+   {:error/code :error.token/name-collision
+    :error/fn #(str (tr "errors.tokens.name-collision" %))}
+
    :error.style-dictionary/missing-reference
    {:error/code :error.style-dictionary/missing-reference
     :error/fn #(str (tr "errors.tokens.missing-references") (str/join " " %))}
diff --git a/frontend/test/frontend_tests/tokens/style_dictionary_test.cljs b/frontend/test/frontend_tests/tokens/style_dictionary_test.cljs
index 1f1609f344..3461298c4d 100644
--- a/frontend/test/frontend_tests/tokens/style_dictionary_test.cljs
+++ b/frontend/test/frontend_tests/tokens/style_dictionary_test.cljs
@@ -58,6 +58,45 @@
                         (get-in resolved-tokens ["borderRadius.largeFn" :errors 0 :error/code])))
                (done))))))))
 
+;; Regression for #9584 — when one active set defines a token named
+;; "a" and another defines "a.b", the tokens-tree builder collapses
+;; them via assoc-in, so StyleDictionary only sees one. Previously
+;; the other vanished from the sidebar entirely; now `resolve-tokens`
+;; tags the dropped token with `:error.token/name-collision` so the
+;; existing broken-pill rendering picks it up.
+
+(t/deftest resolve-tokens-name-collision-test
+  (t/async
+    done
+    (t/testing "tokens colliding with a token-group prefix survive resolution as broken pills"
+      (let [tokens (-> (ctob/make-tokens-lib)
+                       (ctob/add-set (ctob/make-token-set :id (cthi/new-id! :set-1)
+                                                          :name "set-1"))
+                       (ctob/add-set (ctob/make-token-set :id (cthi/new-id! :set-2)
+                                                          :name "set-2"))
+                       (ctob/add-token (cthi/id :set-1)
+                                       (ctob/make-token {:name "a"
+                                                         :value "8px"
+                                                         :type :border-radius}))
+                       (ctob/add-token (cthi/id :set-2)
+                                       (ctob/make-token {:name "a.b"
+                                                         :value "12px"
+                                                         :type :border-radius}))
+                       (ctob/get-all-tokens-map))]
+        (-> (sd/resolve-tokens tokens)
+            (rx/sub!
+             (fn [resolved-tokens]
+               (t/testing "both tokens are present in the resolved map"
+                 (t/is (contains? resolved-tokens "a"))
+                 (t/is (contains? resolved-tokens "a.b")))
+               (t/testing "the colliding token carries the name-collision error"
+                 (let [errors (or (get-in resolved-tokens ["a" :errors])
+                                  (get-in resolved-tokens ["a.b" :errors]))]
+                   (t/is (seq errors))
+                   (t/is (= :error.token/name-collision
+                            (-> errors first :error/code)))))
+               (done))))))))
+
 (t/deftest resolve-tokens-interactive-test
   (t/async
     done
diff --git a/frontend/translations/en.po b/frontend/translations/en.po
index 4ac05d4419..fb4b609978 100644
--- a/frontend/translations/en.po
+++ b/frontend/translations/en.po
@@ -8608,6 +8608,10 @@ msgstr "%s active sets"
 msgid "errors.tokens.number-too-large"
 msgstr "Invalid token value. The resolved value is too large: %s"
 
+#: src/app/main/data/workspace/tokens/errors.cljs:60
+msgid "errors.tokens.name-collision"
+msgstr "Token name %s conflicts with a token group of the same name in another active set."
+
 #: src/app/main/data/workspace/tokens/errors.cljs:73, src/app/main/data/workspace/tokens/warnings.cljs:15
 msgid "errors.tokens.opacity-range"
 msgstr "Opacity must be between 0 and 100% or 0 and 1 (e.g. 50% or 0.5)."