diff --git a/src/applications/almanac/typeahead/AlmanacInterfaceDatasource.php b/src/applications/almanac/typeahead/AlmanacInterfaceDatasource.php
index 3609cb06f6..73ae32938b 100644
--- a/src/applications/almanac/typeahead/AlmanacInterfaceDatasource.php
+++ b/src/applications/almanac/typeahead/AlmanacInterfaceDatasource.php
@@ -1,51 +1,57 @@
 <?php
 
 final class AlmanacInterfaceDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: We should make this browsable, but need to make the result set
+    // orderable by device name.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type an interface name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorAlmanacApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $devices = id(new AlmanacDeviceQuery())
       ->setViewer($viewer)
       ->withNamePrefix($raw_query)
       ->execute();
 
     if ($devices) {
       $interfaces = id(new AlmanacInterfaceQuery())
         ->setViewer($viewer)
         ->withDevicePHIDs(mpull($devices, 'getPHID'))
         ->execute();
     } else {
       $interfaces = array();
     }
 
     if ($interfaces) {
       $handles = id(new PhabricatorHandleQuery())
         ->setViewer($viewer)
         ->withPHIDs(mpull($interfaces, 'getPHID'))
         ->execute();
     } else {
       $handles = array();
     }
 
     $results = array();
     foreach ($handles as $handle) {
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setName($handle->getName())
         ->setPHID($handle->getPHID());
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php b/src/applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php
index 963c0b2ca9..ce77b56f9b 100644
--- a/src/applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php
+++ b/src/applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php
@@ -1,30 +1,35 @@
 <?php
 
 final class DiffusionArcanistProjectDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: We should probably make this browsable, or maybe remove it.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type an arcanist project name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorDiffusionApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $arcprojs = id(new PhabricatorRepositoryArcanistProject())->loadAll();
     foreach ($arcprojs as $proj) {
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setName($proj->getName())
         ->setPHID($proj->getPHID());
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/diffusion/typeahead/DiffusionSymbolDatasource.php b/src/applications/diffusion/typeahead/DiffusionSymbolDatasource.php
index 97ab83f44d..0203ff2971 100644
--- a/src/applications/diffusion/typeahead/DiffusionSymbolDatasource.php
+++ b/src/applications/diffusion/typeahead/DiffusionSymbolDatasource.php
@@ -1,48 +1,54 @@
 <?php
 
 final class DiffusionSymbolDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // This is slightly involved to make browsable, and browsing symbols
+    // does not seem likely to be very useful in any real software project.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type a symbol name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorDiffusionApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     if (strlen($raw_query)) {
       $symbols = id(new DiffusionSymbolQuery())
         ->setViewer($viewer)
         ->setNamePrefix($raw_query)
         ->setLimit(15)
         ->needArcanistProjects(true)
         ->needRepositories(true)
         ->needPaths(true)
         ->execute();
       foreach ($symbols as $symbol) {
         $lang = $symbol->getSymbolLanguage();
         $name = $symbol->getSymbolName();
         $type = $symbol->getSymbolType();
         $proj = $symbol->getArcanistProject()->getName();
 
         $results[] = id(new PhabricatorTypeaheadResult())
           ->setName($name)
           ->setURI($symbol->getURI())
           ->setPHID(md5($symbol->getURI())) // Just needs to be unique.
           ->setDisplayName($name)
           ->setDisplayType(strtoupper($lang).' '.ucwords($type).' ('.$proj.')')
           ->setPriorityType('symb');
       }
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/harbormaster/typeahead/HarbormasterBuildDependencyDatasource.php b/src/applications/harbormaster/typeahead/HarbormasterBuildDependencyDatasource.php
index c1228c9446..997e129bb3 100644
--- a/src/applications/harbormaster/typeahead/HarbormasterBuildDependencyDatasource.php
+++ b/src/applications/harbormaster/typeahead/HarbormasterBuildDependencyDatasource.php
@@ -1,45 +1,50 @@
 <?php
 
 final class HarbormasterBuildDependencyDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: This should be browsable, but fixing it is involved.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type another build step name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorHarbormasterApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
 
     $plan_phid = $this->getParameter('planPHID');
     $step_phid = $this->getParameter('stepPHID');
 
     $steps = id(new HarbormasterBuildStepQuery())
       ->setViewer($viewer)
       ->withBuildPlanPHIDs(array($plan_phid))
       ->execute();
     $steps = mpull($steps, null, 'getPHID');
 
     if (count($steps) === 0) {
       return array();
     }
 
     $results = array();
     foreach ($steps as $phid => $step) {
       if ($step->getPHID() === $step_phid) {
         continue;
       }
 
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setName($step->getName())
         ->setURI('/')
         ->setPHID($phid);
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/legalpad/typeahead/LegalpadDocumentDatasource.php b/src/applications/legalpad/typeahead/LegalpadDocumentDatasource.php
index 853d775184..a536843d0b 100644
--- a/src/applications/legalpad/typeahead/LegalpadDocumentDatasource.php
+++ b/src/applications/legalpad/typeahead/LegalpadDocumentDatasource.php
@@ -1,31 +1,36 @@
 <?php
 
 final class LegalpadDocumentDatasource extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: This should be made browsable.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type a document name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorLegalpadApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $documents = id(new LegalpadDocumentQuery())
       ->setViewer($viewer)
       ->execute();
     foreach ($documents as $document) {
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setPHID($document->getPHID())
         ->setName($document->getMonogram().' '.$document->getTitle());
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/macro/typeahead/PhabricatorMacroDatasource.php b/src/applications/macro/typeahead/PhabricatorMacroDatasource.php
index 339be08fa7..4b8d52b4d4 100644
--- a/src/applications/macro/typeahead/PhabricatorMacroDatasource.php
+++ b/src/applications/macro/typeahead/PhabricatorMacroDatasource.php
@@ -1,33 +1,38 @@
 <?php
 
 final class PhabricatorMacroDatasource extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: This should be made browsable.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type a macro name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorMacroApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $macros = id(new PhabricatorMacroQuery())
       ->setViewer($viewer)
       ->withStatus(PhabricatorMacroQuery::STATUS_ACTIVE)
       ->execute();
 
     foreach ($macros as $macro) {
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setPHID($macro->getPHID())
         ->setName($macro->getName());
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/mailinglists/typeahead/PhabricatorMailingListDatasource.php b/src/applications/mailinglists/typeahead/PhabricatorMailingListDatasource.php
index 53f7d82e0e..c08da2a30d 100644
--- a/src/applications/mailinglists/typeahead/PhabricatorMailingListDatasource.php
+++ b/src/applications/mailinglists/typeahead/PhabricatorMailingListDatasource.php
@@ -1,33 +1,38 @@
 <?php
 
 final class PhabricatorMailingListDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: Make this browsable if we don't delete it before then.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type a mailing list name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorMailingListsApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $lists = id(new PhabricatorMailingListQuery())
       ->setViewer($viewer)
       ->execute();
     foreach ($lists as $list) {
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setName($list->getName())
         ->setURI($list->getURI())
         ->setPHID($list->getPHID());
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/maniphest/typeahead/ManiphestTaskPriorityDatasource.php b/src/applications/maniphest/typeahead/ManiphestTaskPriorityDatasource.php
index 172caea1a6..568aa0636d 100644
--- a/src/applications/maniphest/typeahead/ManiphestTaskPriorityDatasource.php
+++ b/src/applications/maniphest/typeahead/ManiphestTaskPriorityDatasource.php
@@ -1,31 +1,31 @@
 <?php
 
 final class ManiphestTaskPriorityDatasource
   extends PhabricatorTypeaheadDatasource {
 
   public function getPlaceholderText() {
     return pht('Type a task priority name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorManiphestApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $priority_map = ManiphestTaskPriority::getTaskPriorityMap();
     foreach ($priority_map as $value => $name) {
       // NOTE: $value is not a PHID but is unique. This'll work.
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setPHID($value)
         ->setName($name);
     }
 
-    return $results;
+    return $this->filterResultsAgainstTokens($results);
   }
 
 }
diff --git a/src/applications/maniphest/typeahead/ManiphestTaskStatusDatasource.php b/src/applications/maniphest/typeahead/ManiphestTaskStatusDatasource.php
index e7eba2923c..27b3f90386 100644
--- a/src/applications/maniphest/typeahead/ManiphestTaskStatusDatasource.php
+++ b/src/applications/maniphest/typeahead/ManiphestTaskStatusDatasource.php
@@ -1,30 +1,30 @@
 <?php
 
 final class ManiphestTaskStatusDatasource
   extends PhabricatorTypeaheadDatasource {
 
   public function getPlaceholderText() {
     return pht('Type a task status name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorManiphestApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $status_map = ManiphestTaskStatus::getTaskStatusMap();
     foreach ($status_map as $value => $name) {
       // NOTE: $value is not a PHID but is unique. This'll work.
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setPHID($value)
         ->setName($name);
     }
 
-    return $results;
+    return $this->filterResultsAgainstTokens($results);
   }
 }
diff --git a/src/applications/meta/typeahead/PhabricatorApplicationDatasource.php b/src/applications/meta/typeahead/PhabricatorApplicationDatasource.php
index 19b40f727a..18b6683dfc 100644
--- a/src/applications/meta/typeahead/PhabricatorApplicationDatasource.php
+++ b/src/applications/meta/typeahead/PhabricatorApplicationDatasource.php
@@ -1,43 +1,43 @@
 <?php
 
 final class PhabricatorApplicationDatasource
   extends PhabricatorTypeaheadDatasource {
 
   public function getPlaceholderText() {
     return pht('Type an application name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorApplicationsApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $applications = PhabricatorApplication::getAllInstalledApplications();
     foreach ($applications as $application) {
       $uri = $application->getTypeaheadURI();
       if (!$uri) {
         continue;
       }
       $name = $application->getName().' '.$application->getShortDescription();
       $img = 'phui-font-fa phui-icon-view '.$application->getFontIcon();
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setName($name)
         ->setURI($uri)
         ->setPHID($application->getPHID())
         ->setPriorityString($application->getName())
         ->setDisplayName($application->getName())
         ->setDisplayType($application->getShortDescription())
         ->setImageuRI($application->getIconURI())
         ->setPriorityType('apps')
         ->setImageSprite('phabricator-search-icon '.$img);
     }
 
-    return $results;
+    return $this->filterResultsAgainstTokens($results);
   }
 
 }
diff --git a/src/applications/metamta/typeahead/PhabricatorMetaMTAApplicationEmailDatasource.php b/src/applications/metamta/typeahead/PhabricatorMetaMTAApplicationEmailDatasource.php
index bbe5e0d8f6..887aecfd80 100644
--- a/src/applications/metamta/typeahead/PhabricatorMetaMTAApplicationEmailDatasource.php
+++ b/src/applications/metamta/typeahead/PhabricatorMetaMTAApplicationEmailDatasource.php
@@ -1,43 +1,48 @@
 <?php
 
 final class PhabricatorMetaMTAApplicationEmailDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: Make this browsable.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type an application email address...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorMetaMTAApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $emails = id(new PhabricatorMetaMTAApplicationEmailQuery())
       ->setViewer($viewer)
       ->withAddressPrefix($raw_query)
       ->setLimit($this->getLimit())
       ->execute();
 
     if ($emails) {
       $handles = id(new PhabricatorHandleQuery())
         ->setViewer($viewer)
         ->withPHIDs(mpull($emails, 'getPHID'))
         ->execute();
     } else {
       $handles = array();
     }
 
     $results = array();
     foreach ($handles as $handle) {
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setName($handle->getName())
         ->setPHID($handle->getPHID());
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php b/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php
index c0a6c92589..a8658549ec 100644
--- a/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php
+++ b/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php
@@ -1,34 +1,39 @@
 <?php
 
 final class PhabricatorOwnersPackageDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // TODO: Make this browsable.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type a package name...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorOwnersApplication';
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $packages = id(new PhabricatorOwnersPackageQuery())
       ->setViewer($viewer)
       ->execute();
 
     foreach ($packages as $package) {
       $results[] = id(new PhabricatorTypeaheadResult())
         ->setName($package->getName())
         ->setURI('/owners/package/'.$package->getID().'/')
         ->setPHID($package->getPHID());
     }
 
     return $results;
   }
 
 }
diff --git a/src/applications/typeahead/controller/PhabricatorTypeaheadModularDatasourceController.php b/src/applications/typeahead/controller/PhabricatorTypeaheadModularDatasourceController.php
index e2a6de0e43..2672e7d79a 100644
--- a/src/applications/typeahead/controller/PhabricatorTypeaheadModularDatasourceController.php
+++ b/src/applications/typeahead/controller/PhabricatorTypeaheadModularDatasourceController.php
@@ -1,250 +1,255 @@
 <?php
 
 final class PhabricatorTypeaheadModularDatasourceController
   extends PhabricatorTypeaheadDatasourceController {
 
   public function shouldAllowPublic() {
     return true;
   }
 
   public function handleRequest(AphrontRequest $request) {
     $request = $this->getRequest();
     $viewer = $request->getUser();
     $query = $request->getStr('q');
     $is_browse = ($request->getURIData('action') == 'browse');
 
     // Default this to the query string to make debugging a little bit easier.
     $raw_query = nonempty($request->getStr('raw'), $query);
 
     // This makes form submission easier in the debug view.
     $class = nonempty($request->getURIData('class'), $request->getStr('class'));
 
     $sources = id(new PhutilSymbolLoader())
       ->setAncestorClass('PhabricatorTypeaheadDatasource')
       ->loadObjects();
     if (isset($sources[$class])) {
       $source = $sources[$class];
       $source->setParameters($request->getRequestData());
+      $source->setViewer($viewer);
 
       // NOTE: Wrapping the source in a Composite datasource ensures we perform
       // application visibility checks for the viewer, so we do not need to do
       // those separately.
       $composite = new PhabricatorTypeaheadRuntimeCompositeDatasource();
       $composite->addDatasource($source);
 
       $composite
         ->setViewer($viewer)
         ->setQuery($query)
         ->setRawQuery($raw_query);
 
       $hard_limit = 1000;
 
       if ($is_browse) {
+        if (!$composite->isBrowsable()) {
+          return new Aphront404Response();
+        }
+
         $limit = 10;
         $offset = $request->getInt('offset');
 
         if (($offset + $limit) >= $hard_limit) {
           // Offset-based paging is intrinsically slow; hard-cap how far we're
           // willing to go with it.
           return new Aphront404Response();
         }
 
         $composite
           ->setLimit($limit + 1)
           ->setOffset($offset);
       }
 
       $results = $composite->loadResults();
 
       if ($is_browse) {
         $next_link = null;
 
         if (count($results) > $limit) {
           $results = array_slice($results, 0, $limit, $preserve_keys = true);
           if (($offset + (2 * $limit)) < $hard_limit) {
             $next_uri = id(new PhutilURI($request->getRequestURI()))
               ->setQueryParam('offset', $offset + $limit);
 
             $next_link = javelin_tag(
               'a',
               array(
                 'href' => $next_uri,
                 'class' => 'typeahead-browse-more',
                 'sigil' => 'typeahead-browse-more',
                 'mustcapture' => true,
               ),
               pht('More Results'));
           } else {
             // If the user has paged through more than 1K results, don't
             // offer to page any further.
             $next_link = javelin_tag(
               'div',
               array(
                 'class' => 'typeahead-browse-hard-limit',
               ),
               pht('You reach the edge of the abyss.'));
           }
         }
 
         $items = array();
         foreach ($results as $result) {
           $token = PhabricatorTypeaheadTokenView::newForTypeaheadResult(
             $result);
           $items[] = phutil_tag(
             'div',
             array(
               'class' => 'grouped',
             ),
             $token);
         }
 
         $markup = array(
           $items,
           $next_link,
         );
 
         if ($request->isAjax()) {
           $content = array(
             'markup' => hsprintf('%s', $markup),
           );
           return id(new AphrontAjaxResponse())->setContent($content);
         }
 
         $this->requireResource('typeahead-browse-css');
         $this->initBehavior('typeahead-browse');
 
         $input_id = celerity_generate_unique_node_id();
         $frame_id = celerity_generate_unique_node_id();
 
         $config = array(
           'inputID' => $input_id,
           'frameID' => $frame_id,
           'uri' => (string)$request->getRequestURI(),
         );
         $this->initBehavior('typeahead-search', $config);
 
         $search = javelin_tag(
           'input',
           array(
             'type' => 'text',
             'id' => $input_id,
             'class' => 'typeahead-browse-input',
             'autocomplete' => 'off',
             'placeholder' => $source->getPlaceholderText(),
           ));
 
         $frame = phutil_tag(
           'div',
           array(
             'class' => 'typeahead-browse-frame',
             'id' => $frame_id,
           ),
           $markup);
 
         $browser = array(
           phutil_tag(
             'div',
             array(
               'class' => 'typeahead-browse-header',
             ),
             $search),
           $frame,
         );
 
         return $this->newDialog()
           ->setWidth(AphrontDialogView::WIDTH_FORM)
           ->setRenderDialogAsDiv(true)
           ->setTitle(get_class($source)) // TODO: Provide nice names.
           ->appendChild($browser)
           ->addCancelButton('/', pht('Close'));
       }
 
     } else if ($is_browse) {
       return new Aphront404Response();
     } else {
       $results = array();
     }
 
     $content = mpull($results, 'getWireFormat');
 
     if ($request->isAjax()) {
       return id(new AphrontAjaxResponse())->setContent($content);
     }
 
     // If there's a non-Ajax request to this endpoint, show results in a tabular
     // format to make it easier to debug typeahead output.
 
     foreach ($sources as $key => $source) {
       // This can happen with composite sources like user or project, as well
       // generic ones like NoOwner
       if (!$source->getDatasourceApplicationClass()) {
         continue;
       }
       if (!PhabricatorApplication::isClassInstalledForViewer(
         $source->getDatasourceApplicationClass(),
         $viewer)) {
         unset($sources[$key]);
       }
     }
     $options = array_fuse(array_keys($sources));
     asort($options);
 
     $form = id(new AphrontFormView())
       ->setUser($viewer)
       ->setAction('/typeahead/class/')
       ->appendChild(
         id(new AphrontFormSelectControl())
           ->setLabel(pht('Source Class'))
           ->setName('class')
           ->setValue($class)
           ->setOptions($options))
       ->appendChild(
         id(new AphrontFormTextControl())
           ->setLabel(pht('Query'))
           ->setName('q')
           ->setValue($request->getStr('q')))
       ->appendChild(
         id(new AphrontFormTextControl())
           ->setLabel(pht('Raw Query'))
           ->setName('raw')
           ->setValue($request->getStr('raw')))
       ->appendChild(
         id(new AphrontFormSubmitControl())
           ->setValue(pht('Query')));
 
     $form_box = id(new PHUIObjectBoxView())
       ->setHeaderText(pht('Token Query'))
       ->setForm($form);
 
     $table = new AphrontTableView($content);
     $table->setHeaders(
       array(
         pht('Name'),
         pht('URI'),
         pht('PHID'),
         pht('Priority'),
         pht('Display Name'),
         pht('Display Type'),
         pht('Image URI'),
         pht('Priority Type'),
         pht('Icon'),
         pht('Closed'),
         pht('Sprite'),
       ));
 
     $result_box = id(new PHUIObjectBoxView())
       ->setHeaderText(pht('Token Results (%s)', $class))
       ->appendChild($table);
 
     return $this->buildApplicationPage(
       array(
         $form_box,
         $result_box,
       ),
       array(
         'title' => pht('Typeahead Results'),
         'device' => false,
       ));
   }
 
 }
diff --git a/src/applications/typeahead/datasource/PhabricatorTypeaheadCompositeDatasource.php b/src/applications/typeahead/datasource/PhabricatorTypeaheadCompositeDatasource.php
index b1f55190c9..334d9354de 100644
--- a/src/applications/typeahead/datasource/PhabricatorTypeaheadCompositeDatasource.php
+++ b/src/applications/typeahead/datasource/PhabricatorTypeaheadCompositeDatasource.php
@@ -1,68 +1,83 @@
 <?php
 
 abstract class PhabricatorTypeaheadCompositeDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  private $usable;
+
   abstract public function getComponentDatasources();
 
+  public function isBrowsable() {
+    foreach ($this->getUsableDatasources() as $datasource) {
+      if (!$datasource->isBrowsable()) {
+        return false;
+      }
+    }
+
+    return parent::isBrowsable();
+  }
+
   public function getDatasourceApplicationClass() {
     return null;
   }
 
   public function loadResults() {
     $offset = $this->getOffset();
     $limit = $this->getLimit();
 
     $results = array();
     foreach ($this->getUsableDatasources() as $source) {
       $source
         ->setRawQuery($this->getRawQuery())
         ->setQuery($this->getQuery())
         ->setViewer($this->getViewer());
 
       if ($limit) {
         $source->setLimit($offset + $limit);
       }
 
       $results[] = $source->loadResults();
     }
 
     $results = array_mergev($results);
     $results = msort($results, 'getSortKey');
 
     $count = count($results);
     if ($offset || $limit) {
       if (!$limit) {
         $limit = count($results);
       }
 
       $results = array_slice($results, $offset, $limit, $preserve_keys = true);
     }
 
     return $results;
   }
 
   private function getUsableDatasources() {
-    $sources = $this->getComponentDatasources();
-
-    $usable = array();
-    foreach ($sources as $source) {
-      $application_class = $source->getDatasourceApplicationClass();
-
-      if ($application_class) {
-        $result = id(new PhabricatorApplicationQuery())
-          ->setViewer($this->getViewer())
-          ->withClasses(array($application_class))
-          ->execute();
-        if (!$result) {
-          continue;
+    if ($this->usable === null) {
+      $sources = $this->getComponentDatasources();
+
+      $usable = array();
+      foreach ($sources as $source) {
+        $application_class = $source->getDatasourceApplicationClass();
+
+        if ($application_class) {
+          $result = id(new PhabricatorApplicationQuery())
+            ->setViewer($this->getViewer())
+            ->withClasses(array($application_class))
+            ->execute();
+          if (!$result) {
+            continue;
+          }
         }
-      }
 
-      $usable[] = $source;
+        $usable[] = $source;
+      }
+      $this->usable = $usable;
     }
 
-    return $usable;
+    return $this->usable;
   }
 
 }
diff --git a/src/applications/typeahead/datasource/PhabricatorTypeaheadDatasource.php b/src/applications/typeahead/datasource/PhabricatorTypeaheadDatasource.php
index 3d6d2b75f2..a15a248e23 100644
--- a/src/applications/typeahead/datasource/PhabricatorTypeaheadDatasource.php
+++ b/src/applications/typeahead/datasource/PhabricatorTypeaheadDatasource.php
@@ -1,105 +1,176 @@
 <?php
 
 abstract class PhabricatorTypeaheadDatasource extends Phobject {
 
   private $viewer;
   private $query;
   private $rawQuery;
   private $offset;
   private $limit;
   private $parameters = array();
 
   public function setLimit($limit) {
     $this->limit = $limit;
     return $this;
   }
 
   public function getLimit() {
     return $this->limit;
   }
 
   public function setOffset($offset) {
     $this->offset = $offset;
     return $this;
   }
 
   public function getOffset() {
     return $this->offset;
   }
 
   public function setViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
   }
 
   public function getViewer() {
     return $this->viewer;
   }
 
   public function setRawQuery($raw_query) {
     $this->rawQuery = $raw_query;
     return $this;
   }
 
   public function getRawQuery() {
     return $this->rawQuery;
   }
 
   public function setQuery($query) {
     $this->query = $query;
     return $this;
   }
 
   public function getQuery() {
     return $this->query;
   }
 
   public function setParameters(array $params) {
     $this->parameters = $params;
     return $this;
   }
 
   public function getParameters() {
     return $this->parameters;
   }
 
   public function getParameter($name, $default = null) {
     return idx($this->parameters, $name, $default);
   }
 
   public function getDatasourceURI() {
     $uri = new PhutilURI('/typeahead/class/'.get_class($this).'/');
     $uri->setQueryParams($this->parameters);
     return (string)$uri;
   }
 
   abstract public function getPlaceholderText();
   abstract public function getDatasourceApplicationClass();
   abstract public function loadResults();
 
   public static function tokenizeString($string) {
     $string = phutil_utf8_strtolower($string);
     $string = trim($string);
     if (!strlen($string)) {
       return array();
     }
 
     $tokens = preg_split('/\s+|[-\[\]]/', $string);
     return array_unique($tokens);
   }
 
   public function getTokens() {
     return self::tokenizeString($this->getRawQuery());
   }
 
   protected function executeQuery(
     PhabricatorCursorPagedPolicyAwareQuery $query) {
 
     return $query
       ->setViewer($this->getViewer())
       ->setOffset($this->getOffset())
       ->setLimit($this->getLimit())
       ->execute();
   }
 
+
+  /**
+   * Can the user browse through results from this datasource?
+   *
+   * Browsable datasources allow the user to switch from typeahead mode to
+   * a browse mode where they can scroll through all results.
+   *
+   * By default, datasources are browsable, but some datasources can not
+   * generate a meaningful result set or can't filter results on the server.
+   *
+   * @return bool
+   */
+  public function isBrowsable() {
+    return true;
+  }
+
+
+  /**
+   * Filter a list of results, removing items which don't match the query
+   * tokens.
+   *
+   * This is useful for datasources which return a static list of hard-coded
+   * or configured results and can't easily do query filtering in a real
+   * query class. Instead, they can just build the entire result set and use
+   * this method to filter it.
+   *
+   * For datasources backed by database objects, this is often much less
+   * efficient than filtering at the query level.
+   *
+   * @param list<PhabricatorTypeaheadResult> List of typeahead results.
+   * @return list<PhabricatorTypeaheadResult> Filtered results.
+   */
+  protected function filterResultsAgainstTokens(array $results) {
+    $tokens = $this->getTokens();
+    if (!$tokens) {
+      return $results;
+    }
+
+    $map = array();
+    foreach ($tokens as $token) {
+      $map[$token] = strlen($token);
+    }
+
+    foreach ($results as $key => $result) {
+      $rtokens = self::tokenizeString($result->getName());
+
+      // For each token in the query, we need to find a match somewhere
+      // in the result name.
+      foreach ($map as $token => $length) {
+        // Look for a match.
+        $match = false;
+        foreach ($rtokens as $rtoken) {
+          if (!strncmp($rtoken, $token, $length)) {
+            // This part of the result name has the query token as a prefix.
+            $match = true;
+            break;
+          }
+        }
+
+        if (!$match) {
+          // We didn't find a match for this query token, so throw the result
+          // away. Try with the next result.
+          unset($results[$key]);
+          break;
+        }
+      }
+    }
+
+    return $results;
+  }
+
 }
diff --git a/src/applications/typeahead/datasource/PhabricatorTypeaheadMonogramDatasource.php b/src/applications/typeahead/datasource/PhabricatorTypeaheadMonogramDatasource.php
index 267976b773..ebaf3d39d8 100644
--- a/src/applications/typeahead/datasource/PhabricatorTypeaheadMonogramDatasource.php
+++ b/src/applications/typeahead/datasource/PhabricatorTypeaheadMonogramDatasource.php
@@ -1,43 +1,50 @@
 <?php
 
 final class PhabricatorTypeaheadMonogramDatasource
   extends PhabricatorTypeaheadDatasource {
 
+  public function isBrowsable() {
+    // This source isn't meaningfully browsable. Although it's technically
+    // possible to let users browse through every object on an install, there
+    // is no use case for it and it doesn't seem worth building.
+    return false;
+  }
+
   public function getPlaceholderText() {
     return pht('Type an object name...');
   }
 
   public function getDatasourceApplicationClass() {
     return null;
   }
 
   public function loadResults() {
     $viewer = $this->getViewer();
     $raw_query = $this->getRawQuery();
 
     $results = array();
 
     $objects = id(new PhabricatorObjectQuery())
       ->setViewer($viewer)
       ->withNames(array($raw_query))
       ->execute();
     if ($objects) {
       $handles = id(new PhabricatorHandleQuery())
         ->setViewer($viewer)
         ->withPHIDs(mpull($objects, 'getPHID'))
         ->execute();
       $handle = head($handles);
       if ($handle) {
         $results[] = id(new PhabricatorTypeaheadResult())
           ->setName($handle->getFullName())
           ->setDisplayType($handle->getTypeName())
           ->setURI($handle->getURI())
           ->setPHID($handle->getPHID())
           ->setPriorityType('jump');
       }
     }
 
     return $results;
   }
 
 }