Amjad Khan · Adam Bramley
--- a/src/Form/RevisionOverviewForm.php
+++ b/src/Form/RevisionOverviewForm.php

+    // Submit button for the form.
+    $compare_revision_submit = [
+      '#type' => 'submit',
+      '#button_type' => 'primary',
+      '#value' => t('Compare selected revisions'),
+      '#attributes' => [
+        'class' => [
+          'diff-button',
+        ],
+      ],
+    ];
+
+    // If the form is too long add a submit button on top of the screen.
+    if ($revision_count > 5) {
+      // This automatically satisfy if the revisions are greater then 1.
--- a/src/Form/RevisionOverviewForm.php
+++ b/src/Form/RevisionOverviewForm.php

    // Allow comparisons only if there are 2 or more revisions.
    if ($revision_count > 1) {
-      $build['submit'] = [
-        '#type' => 'submit',
-        '#button_type' => 'primary',
-        '#value' => t('Compare selected revisions'),
-        '#attributes' => [
-          'class' => [
-            'diff-button',
-          ],
-        ],
-      ];
+      $build['submit_bottom'] = $compare_revision_submit;
--- a/tests/src/Functional/DiffRevisionTest.php
+++ b/tests/src/Functional/DiffRevisionTest.php
    }
  }

+  /**
+   * Tests pager on diff overview.
+   */
+  public function testRevisionOverviewLong() {