On other email providers such as I used previously (such as PostBox and Outlook) when I downloaded my emails from the webmail automatically the originals always remained in the GMail Inbox.
Since changing to Thunderbird -which is excellent I must say - my only gripe is that the GMail inbox shows blank once I have opened them in TB.
Looking in GMail they do, however, still show in All Mail.
Under settings in GMail I HAVE ticked the box which says 'keep mail in Inbox'....or something similar. Am I doing something wrong?