Hint for user on when the repeat is applied

public/app/features/panel/partials/general_tab.html

@@ -37,7 +37,12 @@
           <option value=""></option>
         </select>
       </div>
+      <div class="gf-form-hint">
+        <div class="gf-form-hint-text muted">
+          Note: You may need to change the variable selection to see this in action.
+        </div>
       </div>
+    </div>
   </div>
 </div>