Only display dropzone if "Show all" is selected.

frontend/app/templates/work_packages.show.html

@@ -162,7 +162,7 @@
           </dl>
         </div>
 
-        <work-package-attachments edit work-package="vm.workPackage"></work-package-attachments>
+        <work-package-attachments edit data-ng-show="!vm.hideEmptyFields || vm.filesExist" work-package="vm.workPackage"></work-package-attachments>
       </div>
     </div>
     <div class="work-packages--right-panel">

frontend/app/work_packages/controllers/index.js

@@ -138,6 +138,7 @@ angular.module('openproject.workPackages.controllers')
     'PERMITTED_MORE_MENU_ACTIONS',
     'HookService',
     '$window',
+    'WorkPackageAttachmentsService',
     require('./work-package-show-controller')
   ])
   .controller('WorkPackagesController', [

frontend/app/work_packages/controllers/work-package-show-controller.js

@@ -53,7 +53,8 @@ module.exports = function($scope,
     WorkPackageAuthorization,
     PERMITTED_MORE_MENU_ACTIONS,
     HookService,
-    $window
+    $window,
+    WorkPackageAttachmentsService
   ) {
 
 
@@ -374,9 +375,14 @@ module.exports = function($scope,
   vm.isSpecified = WorkPackagesDisplayHelper.isSpecified;
   vm.hasNiceStar = WorkPackagesDisplayHelper.hasNiceStar;
   vm.showToggleButton = WorkPackagesDisplayHelper.showToggleButton;
+  vm.filesExist = false;
 
   activate();
 
+  WorkPackageAttachmentsService.hasAttachments(vm.workPackage).then(function(bool) {
+    vm.filesExist = bool;
+  });
+
   function activate() {
     EditableFieldsState.forcedEditState = false;
     $scope.$watch('workPackage.schema', function(schema) {