"Share Desktop" button is always shown regardless of functionality

[459below]

The "Share Desktop" button always shows up, although it should only be displayed if this contact supports Jingle. If the other contact is not running such a client it will always fail. Jingle is also needed for calling and this call button is shown appropriately. So showing the "Share Desktop" button without the call button should be a contradiction. I mentioned the bug here.

I suspect the bug could be here or rather in those classes here, here or maybe here.