As a total novice to the Mac side of the world it is a very steep learning curve for me, being an old bugger to boot! I have created several mailboxes so that I can put my incoming mail into the various different folders that want to.

The latest was to put anything to do with my lovely shiney new iMac into a folder that I called 'iMac'. The box looks different in that it is grey and not blue like all of the other folders. When I try to drag any e-mails into that folder they just bounce back to where they were. If I try to put the same e-mail into any other folder they stay.

Can anyone tell me just what golden rule I am breaking please???