I enabled advanced permissions and learnt how to control area- and block-level permissions for users and user groups. For my content managers, I have taken off all permissions for certain areas (e.g. the ones that hold navigation blocks). Very good, now they can't edit or delete them. But even as they don't have rights to add ANY blocks, the area "Add to <area name>" is still displayed, they can click it, the popup with options "Add Block", "Add Stack", "Paste from clipboard" appears; and even as they can't do anything here (Access denied will be displayed) - imo would be nicer if this "Add to..." area would not be displayed at all in such case.

Is there a way to achieve this? Or is it something which can only be changed by patching the core (or filing a feature request)? I'm using version 5.5.2.1.