Hide the button text of burndown graph in taskboard

app/assets/stylesheets/backlogs/taskboard.css.sass

@@ -227,9 +227,6 @@
 /* dialog */
 
 .task_editor_dialog.ui-dialog
-  .ui-dialog-titlebar-close
-    .ui-button-text
-      display: none
   .ui-widget-header
     background: none
     background-color: #FFFFFF
@@ -249,6 +246,11 @@
     background-color: none
     border: none
 
+.ui-dialog
+  .ui-dialog-titlebar-close
+    .ui-button-text
+      display: none
+
 .dark #task_editor label
   color: #FFFFFF