diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -4756,7 +4756,6 @@
     'PhabricatorSetupIssueView' => 'applications/config/view/PhabricatorSetupIssueView.php',
     'PhabricatorShiftChartFunction' => 'applications/fact/chart/PhabricatorShiftChartFunction.php',
     'PhabricatorShortSite' => 'aphront/site/PhabricatorShortSite.php',
-    'PhabricatorShowFiletreeSetting' => 'applications/settings/setting/PhabricatorShowFiletreeSetting.php',
     'PhabricatorSignDocumentsUserLogType' => 'applications/people/userlog/PhabricatorSignDocumentsUserLogType.php',
     'PhabricatorSimpleEditType' => 'applications/transactions/edittype/PhabricatorSimpleEditType.php',
     'PhabricatorSinChartFunction' => 'applications/fact/chart/PhabricatorSinChartFunction.php',
@@ -11493,7 +11492,6 @@
     'PhabricatorSetupIssueView' => 'AphrontView',
     'PhabricatorShiftChartFunction' => 'PhabricatorPureChartFunction',
     'PhabricatorShortSite' => 'PhabricatorSite',
-    'PhabricatorShowFiletreeSetting' => 'PhabricatorSelectSetting',
     'PhabricatorSignDocumentsUserLogType' => 'PhabricatorUserLogType',
     'PhabricatorSimpleEditType' => 'PhabricatorEditType',
     'PhabricatorSinChartFunction' => 'PhabricatorPureChartFunction',
diff --git a/src/applications/differential/controller/DifferentialRevisionViewController.php b/src/applications/differential/controller/DifferentialRevisionViewController.php
--- a/src/applications/differential/controller/DifferentialRevisionViewController.php
+++ b/src/applications/differential/controller/DifferentialRevisionViewController.php
@@ -474,16 +474,12 @@
         ->setKey('history')
         ->appendChild($history));
 
-    $filetree_on = $viewer->compareUserSetting(
-      PhabricatorShowFiletreeSetting::SETTINGKEY,
-      PhabricatorShowFiletreeSetting::VALUE_ENABLE_FILETREE);
-
     $collapsed_key = PhabricatorFiletreeVisibleSetting::SETTINGKEY;
     $filetree_collapsed = (bool)$viewer->getUserSetting($collapsed_key);
 
     // See PHI811. If the viewer has the file tree on, the files tab with the
     // table of contents is redundant, so default to the "History" tab instead.
-    if ($filetree_on && !$filetree_collapsed) {
+    if (!$filetree_collapsed) {
       $tab_group->selectTab('history');
     }
 
@@ -610,7 +606,7 @@
     $crumbs->setBorder(true);
 
     $nav = null;
-    if ($filetree_on && !$this->isVeryLargeDiff()) {
+    if (!$this->isVeryLargeDiff()) {
       $width_key = PhabricatorFiletreeWidthSetting::SETTINGKEY;
       $width_value = $viewer->getUserSetting($width_key);
 
diff --git a/src/applications/diffusion/controller/DiffusionCommitController.php b/src/applications/diffusion/controller/DiffusionCommitController.php
--- a/src/applications/diffusion/controller/DiffusionCommitController.php
+++ b/src/applications/diffusion/controller/DiffusionCommitController.php
@@ -457,12 +457,8 @@
       $commit,
       $timeline);
 
-    $filetree_on = $viewer->compareUserSetting(
-      PhabricatorShowFiletreeSetting::SETTINGKEY,
-      PhabricatorShowFiletreeSetting::VALUE_ENABLE_FILETREE);
-
     $nav = null;
-    if ($show_changesets && $filetree_on) {
+    if ($show_changesets) {
       $pref_collapse = PhabricatorFiletreeVisibleSetting::SETTINGKEY;
       $collapsed = $viewer->getUserSetting($pref_collapse);
 
diff --git a/src/applications/settings/setting/PhabricatorShowFiletreeSetting.php b/src/applications/settings/setting/PhabricatorShowFiletreeSetting.php
deleted file mode 100644
--- a/src/applications/settings/setting/PhabricatorShowFiletreeSetting.php
+++ /dev/null
@@ -1,42 +0,0 @@
-<?php
-
-final class PhabricatorShowFiletreeSetting
-  extends PhabricatorSelectSetting {
-
-  const SETTINGKEY = 'diff-filetree';
-
-  const VALUE_DISABLE_FILETREE = 0;
-  const VALUE_ENABLE_FILETREE = 1;
-
-  public function getSettingName() {
-    return pht('Show Filetree');
-  }
-
-  protected function getSettingOrder() {
-    return 300;
-  }
-
-  public function getSettingPanelKey() {
-    return PhabricatorDiffPreferencesSettingsPanel::PANELKEY;
-  }
-
-  protected function getControlInstructions() {
-    return pht(
-      'When viewing a revision or commit, you can enable a sidebar showing '.
-      'affected files. When this option is enabled, press {nav %s} to show '.
-      'or hide the sidebar.',
-      'f');
-  }
-
-  public function getSettingDefaultValue() {
-    return self::VALUE_DISABLE_FILETREE;
-  }
-
-  protected function getSelectOptions() {
-    return array(
-      self::VALUE_DISABLE_FILETREE => pht('Disable Filetree'),
-      self::VALUE_ENABLE_FILETREE => pht('Enable Filetree'),
-    );
-  }
-
-}