FileUploader - Small piece of container is not removed.

[marecrismatias1]

Reference:
https://gwtmaterialdesign.github.io/gwt-material-demo/2.1/#fileuploader

Steps:

1. Click the dropzone upload button
2. Select file and click submit
3. After the upload is finished , click the x icon into the list of the files uploaded.
4. You will see that there's a small piece of container that is not removed.