diff --git a/dashboard-dev-screenshots.py b/dashboard-dev-screenshots.py
index 2350f25c..e356c70e 100755
--- a/dashboard-dev-screenshots.py
+++ b/dashboard-dev-screenshots.py
@@ -20,6 +20,12 @@ Hard-won details encoded here:
   copies; pin ?security_tenant=global in the URL or you will screenshot
   old dashboards.
 - Grafana ignores HTTP basic auth for its UI; drive the login form.
+- Grafana lazy-renders panels only when they enter the viewport, so the
+  full-dashboard capture grows the viewport to the dashboard's full height
+  before screenshotting; per-panel viewPanel captures keep the normal size.
+  The capture itself is viewport-sized (not full-page) and capped at
+  12000px, so extremely tall dashboards are truncated at the cap rather
+  than padded out with unrendered blank panels.
 - Splunk panels are the slowest to populate; wait ~25s before capturing.
 """
 
@@ -124,7 +130,32 @@ def grafana(pw):
             timeout=120000,
         )
         page.wait_for_timeout(10000)
-        shot(page, "grafana_dashboard.png")
+        # Grafana only renders a panel's queries once the panel scrolls into
+        # the viewport, so a fixed 1720x1200 viewport leaves everything
+        # below the fold as an empty placeholder in the full-page capture.
+        # Grow the viewport to cover the whole dashboard first so every
+        # panel is "visible" and runs its queries before we screenshot, then
+        # capture that viewport exactly (not full-page) so a dashboard
+        # taller than the cap below is truncated at the cap instead of
+        # having the full-page capture reach past it into unrendered panels.
+        height = page.evaluate(
+            "() => Math.max(document.documentElement.scrollHeight,"
+            " document.body ? document.body.scrollHeight : 0)"
+        )
+        capture_height = min(height + 400, 12000)
+        if height + 400 > 12000:
+            print(
+                "note: dashboard is taller than the 12000px viewport cap; "
+                "grafana_dashboard.png will be truncated at 12000px"
+            )
+        page.set_viewport_size({"width": VIEWPORT["width"], "height": capture_height})
+        page.wait_for_timeout(20000)
+        shot(page, "grafana_dashboard.png", full=False)
+        # Restore the normal viewport for the per-panel captures below; a
+        # viewPanel view fills the viewport, so a grown viewport would
+        # distort those screenshots.
+        page.set_viewport_size(VIEWPORT)
+        page.wait_for_timeout(2000)
         # Zoomed views of the alignment-detail panels.
         for pid, name in ((40, "dkim_details"), (16, "spf_details"), (41, "overview")):
             page.goto(
diff --git a/pyproject.toml b/pyproject.toml
index 7f3f0502..6a276d1c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -91,7 +91,12 @@ build = [
     # stays on requests because its permissive-TLS fallback is built on
     # urllib3's HTTPAdapter machinery.
     "requests>=2.22.0",
-    "ruff",
+    # Pinned exactly for the same reason as pyright: ruff's default rule
+    # set evolves between releases (0.16.0 began flagging this codebase's
+    # str.format() style), so an unpinned version breaks CI without any
+    # code change. Bump deliberately and fix any new findings in the same
+    # PR as the bump.
+    "ruff==0.15.21",
     "sphinx",
     "sphinx_rtd_theme",
 ]