By default, the fileupload component in the Touch UI allows for files to be “dragged and dropped” into it from the DAM and also to be chosen from the local file system using a popup dialog. This is all fine and dandy unless it is undesirable to allow the uploading of files from the local file system (which is a frequent request from our customers). Uploading from the local file system can often lead to broken, or missing assets, or at the very least unmanaged assets. We strongly do not recommend allowing authors to do this.
It should be noted that this solution works for AEM 6.2 and 6.3.
A better solution would be to change the way that the local file upload worked by actually forcing the user to specify what folder in the DAM the asset should be placed. That is easier said than done, unfortunately. We will work on that and update things here on the blog once we have time to get that working. If you have other ideas for how to accomplish this, then be sure to let us know by twitter (@axis41) or email (email@example.com).