A user brought this one to my attention. In the Zimbra Web Client when the phone number zimlet highlights something as phone number there does not appear to be a way to copy and paste this text without including the "callto:" link. I guess the easy answer in our case is to disable the zimlet since we are not using a VOIP system at the moment. However, I'm wondering what we would do if we were using a VOIP system. Are we just missing something here?