diff --git a/webroot/rsrc/js/core/behavior-drag-and-drop-textarea.js b/webroot/rsrc/js/core/behavior-drag-and-drop-textarea.js
index 879a6a086d..4d8629cd8c 100644
--- a/webroot/rsrc/js/core/behavior-drag-and-drop-textarea.js
+++ b/webroot/rsrc/js/core/behavior-drag-and-drop-textarea.js
@@ -1,40 +1,44 @@
 /**
  * @provides javelin-behavior-aphront-drag-and-drop-textarea
  * @requires javelin-behavior
  *           javelin-dom
  *           phabricator-drag-and-drop-file-upload
  *           phabricator-textareautils
  *           phabricator-remarkup-metadata
  */
 
 JX.behavior('aphront-drag-and-drop-textarea', function(config) {
 
   var target = JX.$(config.target);
 
   if (JX.PhabricatorDragAndDropFileUpload.isSupported()) {
     var drop = new JX.PhabricatorDragAndDropFileUpload(target)
       .setURI(config.uri)
       .setChunkThreshold(config.chunkThreshold);
 
     drop.listen('didBeginDrag', function() {
       JX.DOM.alterClass(target, config.activatedClass, true);
     });
 
     drop.listen('didEndDrag', function() {
       JX.DOM.alterClass(target, config.activatedClass, false);
     });
 
     drop.listen('didUpload', function(file) {
       JX.TextAreaUtils.insertFileReference(target, file);
 
-      var metadata = new JX.RemarkupMetadata(config.remarkupMetadataValue,
-        config.remarkupMetadataID);
-      var phids = metadata.getMetadata('attachedFilePHIDs', []);
-      phids.push(file.getPHID());
-      metadata.setMetadata('attachedFilePHIDs', phids);
+      if(config.remarkupMetadataID) {
+        // Try to auto-attach files by default
+        // https://we.phorge.it/T15106
+        var metadata = new JX.RemarkupMetadata(config.remarkupMetadataValue,
+          config.remarkupMetadataID);
+        var phids = metadata.getMetadata('attachedFilePHIDs', []);
+        phids.push(file.getPHID());
+        metadata.setMetadata('attachedFilePHIDs', phids);
+      }
     });
 
     drop.start();
   }
 
 });