diff --git a/tools/check_cowork_screen.py b/tools/check_cowork_screen.py
index 5e54e74..5da12c4 100644
--- a/tools/check_cowork_screen.py
+++ b/tools/check_cowork_screen.py
@@ -87,6 +87,21 @@ def main() -> int:
             fails.append(f"thieu nut {name} tren thanh cong cu")
     print(f"nut tren thanh cong cu: {c.skills_btn.text()!r}, {c._new_btn.text()!r}")
 
+    # the drawing gives Cowork two columns; History lives in the rail's RECENTS
+    # and its pane arrives folded to the strip the drawing keeps
+    w = win.workspace
+    sb = w._sidebar
+    print(f"vao Cowork: History gap={sb.is_collapsed()} rong={sb.width()}px")
+    if not sb.is_collapsed():
+        fails.append("pane Lich su mo san — man Cowork thanh 3 cot")
+    w.show_history_pane()
+    app.processEvents()
+    print(f"sau 'Tat ca project…': History gap={sb.is_collapsed()} rong={sb.width()}px")
+    if sb.is_collapsed():
+        fails.append("'Tat ca project…' khong mo duoc pane Lich su")
+    w._on_history_fold(True)
+    app.processEvents()
+
     # one heading on the files panel, with the chevron at its right — the
     # drawing has "TỆP ĐẦU RA (3) ›" and nothing above it
     from PySide6.QtCore import QPoint as _QP
diff --git a/ui/workspace_tab.py b/ui/workspace_tab.py
index 82dbb9c..6ea23c3 100644
--- a/ui/workspace_tab.py
+++ b/ui/workspace_tab.py
@@ -110,6 +110,9 @@ class WorkspaceTab(QWidget):
         super().__init__()
         self.ctx = ctx
         self._current_id = ""
+        # True once the user asks for the full History panel; until then Cowork
+        # opens with it folded, as the drawing lays the screen out.
+        self._history_opened = False
         # Shared widgets embedded as per-project sub-tabs (None in unit tests
         # that only drive project management).
         self._cowork = cowork
@@ -311,11 +314,16 @@ class WorkspaceTab(QWidget):
         sb = self._sidebar
         sb.open_chat.connect(self._on_sidebar_open)
         sb.new_chat.connect(self._on_sidebar_new)
-        sb.collapse_requested.connect(lambda: self._set_sidebar_collapsed(True))
-        sb.expand_requested.connect(lambda: self._set_sidebar_collapsed(False))
+        sb.collapse_requested.connect(lambda: self._on_history_fold(True))
+        sb.expand_requested.connect(lambda: self._on_history_fold(False))
         sb.refresh_requested.connect(self._on_sidebar_refresh)
         sb.history_changed.connect(self._reload_threads)
 
+    def _on_history_fold(self, collapsed: bool) -> None:
+        """Remember what the user chose, so switching screens does not undo it."""
+        self._history_opened = not collapsed
+        self._set_sidebar_collapsed(collapsed)
+
     def _set_sidebar_collapsed(self, collapsed: bool) -> None:
         """Collapse/expand History sidebar and redistribute splitter space so
         the Cowork chat area fills the freed width (same pattern as
@@ -404,11 +412,14 @@ class WorkspaceTab(QWidget):
         narrow = getattr(self, "_is_narrow", False)
         if self._sidebar is not None:
             self._sidebar.setVisible(on_cowork)
-            # Auto-expand History when entering Cowork — unless the window is too
-            # narrow to hold it, in which case expanding it here would undo the
-            # fold made moments earlier and clip the chat again.
-            if on_cowork:
-                self._sidebar.set_collapsed(narrow)
+            # The drawing gives Cowork two columns — the transcript and the
+            # files panel — and moves history to the rail's RECENTS. Its own
+            # "Vấn đề" note is that three panes squeezed the conversation below
+            # 60% of the width. So History arrives folded to its strip: the
+            # chevron the drawing keeps, one click from the full panel, and
+            # "Tất cả project…" in RECENTS opens it outright.
+            if on_cowork and not self._history_opened:
+                self._sidebar.set_collapsed(True)
         # QSplitter ignores hidden panes, but the freed width isn't handed to
         # the remaining panes deterministically — set explicit sizes after any
         # pane toggle (same lesson as _set_projects_collapsed).
@@ -702,6 +713,7 @@ class WorkspaceTab(QWidget):
         filters, pin, rename, multi-select delete and the context menu all still
         live in this panel.
         """
+        self._history_opened = True
         self._set_sidebar_collapsed(False)
         self._show_cowork_tab()