disable auto link to dropbox and google drive from zoho mail

I am testing several cloud storage options which should have absolutely nothing to do with my zoho mail account. My zoho email address is not associated with any cloud storage service. At least, not by me. I use zoho's free email service and the calendar. I have Dropbox and Google Drive installed on my desktop machine for testing and when I login to zoho to check my email zoho links to those apps. You will notice this in the mail compose window where tabs for dropbox and google now appear, I suppose in case you want get a file from those boxes to attach to an email.

But I want to disable this behavior and cannot. I object strongly to anyone's software app sticking its nose into my hard drive to see what's installed there and then RUNNING apps without my permission. This should absolutely never be done unless the user accepts and installs the option. How can I disable this intrusive feature?