Steps to reproduce:
- Use any browser with HTML5 file upload capability (Chrome for example).
- In computer OS (tested with Ubuntu), open a folder navigation window where it contains a file (the small weight the better).
- Go to Control Panel --> Liferay --> Documents & Media.
- Drag file and drop into Documents & Media initial page.
- You will see the "Completed" message showing in the middle of the file.
- Drag & drop the file again.
Expected behavior: You should see an error message like "Please enter a unique name" somewhere
Actual behavior: No error message shows. This can make users think upload was succesful. But after refreshing page, file isn't there anymore.