I struggled a bit to remove the capability to edit the dashboard if a student (or any other role) is logged in. Easy to unserstand is go to Site Administration – Users – Permissions – Define roles – Student role – Edit and unflag the following my:manageblocks tag:editblocks user:manageownblocks user:manageblocks site:manageblocks however a student is also a logged user and then is necessary to do this same procedure for authenticated users. And the game is done!