Seeing the "All Mail" folder of gmail email accounts in Mail app
Why can't I see the "All Mail" folder of all my gmail accounts when using the iPad Mail app? I can see some of them, but not all. The reason to look at this folder is sometimes I have to read emails that I have inadvertently archived. I realise that I can always look for archived emails in the "All Mail" folder in gmail itself through a regular web browser, but my question is why can I see the "All Mail" folder (and hence read archived emails) in the Mail app for some gmail accounts and not others?
If this is not clear, here I explain more... I have several free gmail accounts and my university email account, which is actually a gmail driven email account. I manage my emails using the iPad Mail app. When I open the mail app, in the top half of the left column, i see the Inboxes, while on the bottom half there are the Accounts of the mailboxes. In the Accounts part, when I tap on the free gmail accounts, I can see the "All Mail" folder as one of the several folders in the account, but when I tap on my university (gmail driven) account, there is no such "All Mail" folder. Why is this?
Thanks for any help given!