diff --git a/resources/celerity/map.php b/resources/celerity/map.php
index 8f22b91818..a41af25a7e 100644
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -507,7 +507,7 @@ return array(
     'rsrc/js/phui/behavior-phui-object-box-tabs.js' => '2bfa2836',
     'rsrc/js/phuix/PHUIXActionListView.js' => 'b5c256b8',
     'rsrc/js/phuix/PHUIXActionView.js' => '8cf6d262',
-    'rsrc/js/phuix/PHUIXAutocomplete.js' => '8bbbad27',
+    'rsrc/js/phuix/PHUIXAutocomplete.js' => 'fc10c813',
     'rsrc/js/phuix/PHUIXDropdownMenu.js' => 'bd4c8dca',
     'rsrc/js/phuix/PHUIXFormControl.js' => '8fba1997',
     'rsrc/js/phuix/PHUIXIconView.js' => 'bff6884b',
@@ -836,7 +836,7 @@ return array(
     'phui-workpanel-view-css' => 'adec7699',
     'phuix-action-list-view' => 'b5c256b8',
     'phuix-action-view' => '8cf6d262',
-    'phuix-autocomplete' => '8bbbad27',
+    'phuix-autocomplete' => 'fc10c813',
     'phuix-dropdown-menu' => 'bd4c8dca',
     'phuix-form-control-view' => '8fba1997',
     'phuix-icon-view' => 'bff6884b',
@@ -1489,12 +1489,6 @@ return array(
       'javelin-stratcom',
       'javelin-vector',
     ),
-    '8bbbad27' => array(
-      'javelin-install',
-      'javelin-dom',
-      'phuix-icon-view',
-      'phabricator-prefab',
-    ),
     '8bdb2835' => array(
       'phui-fontkit-css',
     ),
@@ -2092,6 +2086,12 @@ return array(
       'javelin-behavior-device',
       'phabricator-keyboard-shortcut',
     ),
+    'fc10c813' => array(
+      'javelin-install',
+      'javelin-dom',
+      'phuix-icon-view',
+      'phabricator-prefab',
+    ),
     'fc91ab6c' => array(
       'javelin-behavior',
       'javelin-dom',
diff --git a/webroot/rsrc/js/phuix/PHUIXAutocomplete.js b/webroot/rsrc/js/phuix/PHUIXAutocomplete.js
index b94688e086..beb3660718 100644
--- a/webroot/rsrc/js/phuix/PHUIXAutocomplete.js
+++ b/webroot/rsrc/js/phuix/PHUIXAutocomplete.js
@@ -600,19 +600,26 @@ JX.install('PHUIXAutocomplete', {
         return false;
       }
 
-      // If the user types a string like "@username:" (with a trailing comma),
+      // If the user types a string like "@username:" (with a trailing colon),
       // then presses tab or return to pick the completion, don't destroy the
       // trailing character.
       var suffixes = this._getSuffixes();
       var value = this._value;
+      var found_suffix = false;
       for (var ii = 0; ii < suffixes.length; ii++) {
         var last = value.substring(value.length - suffixes[ii].length);
         if (last == suffixes[ii]) {
           ref += suffixes[ii];
+          found_suffix = true;
           break;
         }
       }
 
+      // If we didn't find an existing suffix, add a space.
+      if (!found_suffix) {
+        ref = ref + ' ';
+      }
+
       area.value = text.substring(0, head - 1) + ref + text.substring(tail);
 
       var end = head + ref.length;