diff --git a/pylib/anki/decks.py b/pylib/anki/decks.py
index 1f491a8a4..27949a30f 100644
--- a/pylib/anki/decks.py
+++ b/pylib/anki/decks.py
@@ -12,6 +12,7 @@ from anki import hooks
 from anki.consts import *
 from anki.errors import DeckRenameError
 from anki.lang import _
+from anki.rsbackend import DeckTreeNode
 from anki.utils import ids2str, intTime
 
 # legacy code may pass this in as the type argument to .id()
@@ -175,6 +176,16 @@ class DeckManager:
     def deck_tree(self) -> pb.DeckTreeNode:
         return self.col.backend.deck_tree(include_counts=False)
 
+    @classmethod
+    def find_deck_in_tree(cls, node: DeckTreeNode, deck_id: int) -> Optional[DeckTreeNode]:
+        if node.deck_id == deck_id:
+            return node
+        for child in node.children:
+            match = cls.find_deck_in_tree(child, deck_id)
+            if match:
+                return match
+        return None
+
     def all(self) -> List:
         "All decks. Expensive; prefer all_names_and_ids()"
         return self.get_all_legacy()
diff --git a/qt/aqt/deckbrowser.py b/qt/aqt/deckbrowser.py
index 5470dad0c..73c9e05d6 100644
--- a/qt/aqt/deckbrowser.py
+++ b/qt/aqt/deckbrowser.py
@@ -268,18 +268,10 @@ where id > ?""",
 
     def _collapse(self, did: int) -> None:
         self.mw.col.decks.collapse(did)
-        self._toggle_collapsed_in_node(did, self._dueTree)
-        self._renderPage(reuse=True)
-
-    def _toggle_collapsed_in_node(self, deck_id: int, node: DeckTreeNode) -> bool:
-        "Toggle collapsed on deck in tree. Returns true if found."
-        if node.deck_id == deck_id:
+        node = self.mw.col.decks.find_deck_in_tree(self._dueTree, did)
+        if node:
             node.collapsed = not node.collapsed
-            return True
-        for child in node.children:
-            if self._toggle_collapsed_in_node(deck_id, child):
-                return True
-        return False
+        self._renderPage(reuse=True)
 
     def _dragDeckOnto(self, draggedDeckDid, ontoDeckDid):
         try: