diff --git a/app.py b/app.py
index d913790..c8b8202 100644
--- a/app.py
+++ b/app.py
@@ -416,6 +416,21 @@ class MainWindow(QMainWindow):
             self._update_dock_guard()
             self.help_agent.reposition()
             self.help_agent.raise_()
+        # Build GraphRAG's browser view and first graph once the window is up
+        # and idle, so clicking GraphRAG does not sit on an empty view while
+        # both happen. 3s is after the first paint and any startup refresh.
+        if not getattr(self, "_graph_prewarmed", False):
+            self._graph_prewarmed = True
+            QTimer.singleShot(3000, self._prewarm_graph)
+
+    def _prewarm_graph(self) -> None:
+        view = getattr(self, "structure", None)
+        if view is None or not hasattr(view, "prewarm"):
+            return
+        try:
+            view.prewarm()
+        except Exception:  # noqa: BLE001 — a warm-up must never break the app
+            pass
 
     # ---- i18n ----------------------------------------------------------
     def _retranslate(self) -> None:
diff --git a/tools/check_graphrag_rescan.py b/tools/check_graphrag_rescan.py
index c65038b..860a50c 100644
--- a/tools/check_graphrag_rescan.py
+++ b/tools/check_graphrag_rescan.py
@@ -50,24 +50,39 @@ def main() -> int:
     win.show()
     app.processEvents()
     st, w = win.structure, win.workspace
-    fails = []
+    fails: list[str] = []
 
-    # first visit builds the view and scans once
-    win._goto(win._ROW_WORKSPACE, w._graphrag_tab_idx)
+    # startup itself must not build any of it
+    if st.web is not None or st._graph is not None:
+        fails.append("dung san do thi ngay luc khoi dong — startup phai nhe")
+
+    # the idle warm-up builds the browser view and the first graph off the
+    # click path (MainWindow fires this on a 3s timer; call it directly here)
+    win._prewarm_graph()
     deadline = time.monotonic() + 30
     while st._graph is None and time.monotonic() < deadline:
         app.processEvents()
         time.sleep(0.02)
     if st._graph is None:
-        print("FAIL  lan dau khong dung duoc do thi")
+        print("FAIL  lam nong khong dung duoc do thi")
         sys.stdout.flush()
         os._exit(1)
+    print(f"sau khi lam nong: web={'co' if st.web else 'chua'} do thi={'co' if st._graph else 'chua'}")
 
     calls = {"scan": 0, "html": 0}
     real_scan, real_html = st._scan, st._render_d3
     st._scan = lambda: (calls.__setitem__("scan", calls["scan"] + 1), real_scan())[1]
     st._render_d3 = lambda: (calls.__setitem__("html", calls["html"] + 1), real_html())[1]
 
+    # ...so the click itself does nothing but show it — this is the flash
+    t0 = time.monotonic()
+    win._goto(win._ROW_WORKSPACE, w._graphrag_tab_idx)
+    app.processEvents()
+    print(f"bam vao GraphRAG: {(time.monotonic() - t0) * 1000:.0f}ms "
+          f"_scan={calls['scan']} setHtml={calls['html']}")
+    if calls["scan"] or calls["html"]:
+        fails.append("bam vao GraphRAG van phai quet/nap lai trang — con chop trang")
+
     # re-entering an unchanged graph must not rebuild anything
     for _ in range(3):
         win._goto(win._ROW_WORKSPACE, w._project_tab_idx)
diff --git a/ui/structure_graph_view.py b/ui/structure_graph_view.py
index eb7a4c6..b195bf0 100644
--- a/ui/structure_graph_view.py
+++ b/ui/structure_graph_view.py
@@ -495,10 +495,31 @@ class StructureGraphView(QWidget):
             f'<pre style="white-space:pre-wrap; font-family:Consolas,monospace; '
             f'font-size:12px;">{html.escape(text)}</pre>')
 
+    def prewarm(self) -> None:
+        """Pay for the graph view before it is clicked on, not during.
+
+        Opening GraphRAG built a QWebEngineView (~140ms) and scanned the project
+        (~485ms) while an empty browser sat on screen — long enough, and white
+        enough, to read as the app restarting itself. Called from an idle timer
+        after the window is up, so startup itself is unaffected; the memory the
+        lazy construction was saving is spent a few seconds later instead.
+        """
+        if not _HAS_WEB or self.web is not None:
+            return
+        self._ensure_web()
+        if self._graph is None and self.path_edit.text().strip():
+            self._needs_scan = False
+            self._scan()          # runs on a worker thread
+
     def _ensure_web(self) -> None:
         if self.web is not None or not _HAS_WEB:
             return
         self.web = QWebEngineView()
+        # Blank the page in the app's own background first. A fresh
+        # QWebEngineView paints white, and on a dark theme that white rectangle
+        # WAS the flash — it showed for as long as the first scan took.
+        self.web.setHtml(
+            f"<body style='margin:0;background:{current_palette().bg}'></body>")
         self._bridge = _Bridge()
         self._channel = QWebChannel()
         self._channel.registerObject("py", self._bridge)