diff --git a/src/applications/differential/view/DifferentialAddCommentView.php b/src/applications/differential/view/DifferentialAddCommentView.php
--- a/src/applications/differential/view/DifferentialAddCommentView.php
+++ b/src/applications/differential/view/DifferentialAddCommentView.php
@@ -67,6 +67,9 @@
       'resign' => pht('Suggest Reviewers'),
     );
 
+    $mailable_source = new PhabricatorMetaMTAMailableDatasource();
+    $reviewer_source = new PhabricatorProjectOrUserDatasource();
+
     $form = new AphrontFormView();
     $form
       ->setWorkflow(true)
@@ -88,7 +91,8 @@
           ->setControlID('add-reviewers')
           ->setControlStyle($enable_reviewers ? null : 'display: none')
           ->setID('add-reviewers-tokenizer')
-          ->setDisableBehavior(true))
+          ->setDisableBehavior(true)
+          ->setDatasource($reviewer_source))
       ->appendControl(
         id(new AphrontFormTokenizerControl())
           ->setLabel(pht('Add Subscribers'))
@@ -96,7 +100,8 @@
           ->setControlID('add-ccs')
           ->setControlStyle($enable_ccs ? null : 'display: none')
           ->setID('add-ccs-tokenizer')
-          ->setDisableBehavior(true))
+          ->setDisableBehavior(true)
+          ->setDatasource($mailable_source))
       ->appendChild(
         id(new PhabricatorRemarkupControl())
           ->setName('comment')
@@ -108,9 +113,6 @@
         id(new AphrontFormSubmitControl())
           ->setValue(pht('Submit')));
 
-    $mailable_source = new PhabricatorMetaMTAMailableDatasource();
-    $reviewer_source = new PhabricatorProjectOrUserDatasource();
-
     Javelin::initBehavior(
       'differential-add-reviewers-and-ccs',
       array(
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
@@ -677,6 +677,9 @@
 
     $actions = $this->getAuditActions($commit, $audit_requests);
 
+    $mailable_source = new PhabricatorMetaMTAMailableDatasource();
+    $auditor_source = new DiffusionAuditorDatasource();
+
     $form = id(new AphrontFormView())
       ->setUser($user)
       ->setAction('/audit/addcomment/')
@@ -694,7 +697,8 @@
           ->setControlID('add-auditors')
           ->setControlStyle('display: none')
           ->setID('add-auditors-tokenizer')
-          ->setDisableBehavior(true))
+          ->setDisableBehavior(true)
+          ->setDatasource($auditor_source))
       ->appendControl(
         id(new AphrontFormTokenizerControl())
           ->setLabel(pht('Add CCs'))
@@ -702,7 +706,8 @@
           ->setControlID('add-ccs')
           ->setControlStyle('display: none')
           ->setID('add-ccs-tokenizer')
-          ->setDisableBehavior(true))
+          ->setDisableBehavior(true)
+          ->setDatasource($mailable_source))
       ->appendChild(
         id(new PhabricatorRemarkupControl())
           ->setLabel(pht('Comments'))
@@ -718,9 +723,6 @@
     $header->setHeader(
       $is_serious ? pht('Audit Commit') : pht('Creative Accounting'));
 
-    $mailable_source = new PhabricatorMetaMTAMailableDatasource();
-    $auditor_source = new DiffusionAuditorDatasource();
-
     Javelin::initBehavior(
       'differential-add-reviewers-and-ccs',
       array(
diff --git a/src/applications/maniphest/controller/ManiphestTaskDetailController.php b/src/applications/maniphest/controller/ManiphestTaskDetailController.php
--- a/src/applications/maniphest/controller/ManiphestTaskDetailController.php
+++ b/src/applications/maniphest/controller/ManiphestTaskDetailController.php
@@ -182,6 +182,10 @@
       $draft_text = null;
     }
 
+    $projects_source = new PhabricatorProjectDatasource();
+    $users_source = new PhabricatorPeopleDatasource();
+    $mailable_source = new PhabricatorMetaMTAMailableDatasource();
+
     $comment_form = new AphrontFormView();
     $comment_form
       ->setUser($user)
@@ -209,7 +213,8 @@
           ->setControlID('assign_to')
           ->setControlStyle('display: none')
           ->setID('assign-tokenizer')
-          ->setDisableBehavior(true))
+          ->setDisableBehavior(true)
+          ->setDatasource($users_source))
       ->appendControl(
         id(new AphrontFormTokenizerControl())
           ->setLabel(pht('CCs'))
@@ -217,7 +222,8 @@
           ->setControlID('ccs')
           ->setControlStyle('display: none')
           ->setID('cc-tokenizer')
-          ->setDisableBehavior(true))
+          ->setDisableBehavior(true)
+          ->setDatasource($mailable_source))
       ->appendChild(
         id(new AphrontFormSelectControl())
           ->setLabel(pht('Priority'))
@@ -233,7 +239,8 @@
           ->setControlID('projects')
           ->setControlStyle('display: none')
           ->setID('projects-tokenizer')
-          ->setDisableBehavior(true))
+          ->setDisableBehavior(true)
+          ->setDatasource($projects_source))
       ->appendChild(
         id(new AphrontFormFileControl())
           ->setLabel(pht('File'))
@@ -260,10 +267,6 @@
       PhabricatorTransactions::TYPE_EDGE        => 'projects',
     );
 
-    $projects_source = new PhabricatorProjectDatasource();
-    $users_source = new PhabricatorPeopleDatasource();
-    $mailable_source = new PhabricatorMetaMTAMailableDatasource();
-
     $tokenizer_map = array(
       PhabricatorTransactions::TYPE_EDGE => array(
         'id'          => 'projects-tokenizer',
diff --git a/src/view/form/control/AphrontFormTokenizerControl.php b/src/view/form/control/AphrontFormTokenizerControl.php
--- a/src/view/form/control/AphrontFormTokenizerControl.php
+++ b/src/view/form/control/AphrontFormTokenizerControl.php
@@ -51,17 +51,15 @@
     }
 
     $datasource = $this->datasource;
-    if ($datasource) {
-      $datasource->setViewer($this->getUser());
+    if (!$datasource) {
+      throw new Exception(
+        pht('You must set a datasource to use a TokenizerControl.'));
     }
+    $datasource->setViewer($this->getUser());
 
     $placeholder = null;
     if (!strlen($this->placeholder)) {
-      if ($datasource) {
-        $placeholder = $datasource->getPlaceholderText();
-      }
-    } else {
-      $placeholder = $this->placeholder;
+      $placeholder = $datasource->getPlaceholderText();
     }
 
     $tokens = array();
@@ -71,14 +69,13 @@
         $token = PhabricatorTypeaheadTokenView::newFromHandle($handles[$value]);
       } else {
         $token = null;
-        if ($datasource) {
-          $function = $datasource->parseFunction($value);
-          if ($function) {
-            $token_list = $datasource->renderFunctionTokens(
-              $function['name'],
-              array($function['argv']));
-            $token = head($token_list);
-          }
+
+        $function = $datasource->parseFunction($value);
+        if ($function) {
+          $token_list = $datasource->renderFunctionTokens(
+            $function['name'],
+            array($function['argv']));
+          $token = head($token_list);
         }
 
         if (!$token) {
@@ -105,17 +102,10 @@
       $username = $this->user->getUsername();
     }
 
-    $datasource_uri = null;
-    $browse_uri = null;
-    if ($datasource) {
-      $datasource->setViewer($this->getUser());
-
-      $datasource_uri = $datasource->getDatasourceURI();
-
-      $browse_uri = $datasource->getBrowseURI();
-      if ($browse_uri) {
-        $template->setBrowseURI($browse_uri);
-      }
+    $datasource_uri = $datasource->getDatasourceURI();
+    $browse_uri = $datasource->getBrowseURI();
+    if ($browse_uri) {
+      $template->setBrowseURI($browse_uri);
     }
 
     if (!$this->disableBehavior) {