[DLP] Block Dropbox, Drive, Skydrive desktop apps

I wonder if there's a way to block upload from dropbox, drive, skydrive desktop apps using DLP Endpoint

Sites such as dropbox, drive and skydrive can be block [using Application Monitoring], but its desktop apps can't. 

I add such applications to Application Monitoring page, but it's still uploading :(

Hope anyone knows how-to or maybe a workaround.

Thanks a lot