diff --git a/electionpage/tests.py b/electionpage/tests.py
index 1a75a71c..f946bb39 100644
--- a/electionpage/tests.py
+++ b/electionpage/tests.py
@@ -26,6 +26,7 @@
 from selenium.common.exceptions import NoSuchElementException, StaleElementReferenceException
 from selenium.webdriver.common.by import By
 from selenium.webdriver.support import expected_conditions as EC
+from selenium.webdriver.support.ui import WebDriverWait
 
 from common.testUtils import TestHelpers
 from electionpage.models import ElectionPage, ScrapableElectionPage, SingleSourceElectionPage
@@ -195,8 +196,8 @@ def submit_with_num_elections_and_get_error(num, expectReload):
             self.browser.find_element(By.ID, "submit").click()
 
             if expectReload:
-                self._ensure_eventually_asserts(
-                    lambda: EC.staleness_of(bodyElement))
+                # Wait for the navigation: the old page's body goes stale
+                WebDriverWait(self.browser, timeout=10).until(EC.staleness_of(bodyElement))
 
             try:
                 return self.browser.find_element(
diff --git a/static/datatable/src/datatable.ts b/static/datatable/src/datatable.ts
index cfae52be..c33ba92a 100644
--- a/static/datatable/src/datatable.ts
+++ b/static/datatable/src/datatable.ts
@@ -453,8 +453,9 @@ export default class RcvisDataTable {
                 this.toJson(this.table.getData()));
         }
 
-        // Prepare the mock form
-        const form = document.getElementsByTagName('form')[0];
+        // Prepare the mock form: the upload form by id, since the page has other
+        // forms too (e.g. the logout form in the header)
+        const form = document.getElementById('form');
         const data = $(form).serializeArray();
 
         // AJAX to check if it would survive all serverside processing
diff --git a/static/visualizer/theme.css b/static/visualizer/theme.css
index d8c0a793..90eeb176 100644
--- a/static/visualizer/theme.css
+++ b/static/visualizer/theme.css
@@ -264,6 +264,31 @@ h1, h2, h3, h4, h5, h6 {
   color: var(--rcv-brand);
 }
 
+.nav-logout-form {
+  display: inline;
+  margin: 0;
+}
+
+.nav-logout-button {
+  padding: 0;
+  border: 0;
+  background: none;
+  font: inherit;
+  color: var(--rcv-brand);
+  cursor: pointer;
+}
+
+.nav-logout-button:hover {
+  color: var(--rcv-brand-deep);
+  text-decoration: underline;
+}
+
+.nav-logout-button:focus-visible {
+  outline: 2px solid var(--rcv-brand);
+  outline-offset: 2px;
+  border-radius: 3px;
+}
+
 /* ------------------------------------------------------------------ */
 /* Visualization tab bar (the /v/ page puts its tabs in the header)     */
 /* ------------------------------------------------------------------ */
diff --git a/templates/visualizer/uploadFile.html b/templates/visualizer/uploadFile.html
index 3db0d727..cae30f9e 100644
--- a/templates/visualizer/uploadFile.html
+++ b/templates/visualizer/uploadFile.html
@@ -6,11 +6,15 @@
 {% endblock %}
 
 {% block navlinks %}
-<p class="nav-userinfo">
+<div class="nav-userinfo">
   Logged in as <strong>{{ user.username }}</strong>.
   <br/>
-  <a href="{% url 'logout' %}">Log out</a>?
-</p>
+  {# Django 5 only accepts POST for logout, so this is a form styled as a link #}
+  <form method="post" action="{% url 'logout' %}" class="nav-logout-form">
+    {% csrf_token %}
+    <button type="submit" class="nav-logout-button">Log out</button>?
+  </form>
+</div>
 {% endblock %}
 
 {% block maincontent %}