When it comes to managing my Gmail account on my BlackBerry Z10, I learned the hard way that it’s not always as simple as it looks. This is especially true as I added my account using the IMAP protocol.
One of the things I didn’t realize is that deleting an e-mail off my device did not act in quite the same manner it had on my BlackBerry Bold 9900. Rather than sending deleting items to the trash, they were archived instead. As you can imagine, suddenly discovering hundreds of items there when logging in via my desktop was not a pleasant sight.
In true CrackBerry fashion I scoured the forums until a workaround was found that would ensure I could delete e-mails without being in front of my computer.
From your desktop computer, login to your Gmail account
Click on the gear in the upper right and select Settings from the dropdown
Go to the Forwarding and POP/IMAP tab
Go to the IMAP Access option
Below the heading "When I mark a message in IMAP as deleted," choose the option Auto-Expunge off – Wait for the client to update the server
Under the "When a message is marked as deleted and expunged from the last visible IMAP folder," select the box next to Move the message to the Trash
Click on Save Changes at the bottom of the screen
Under the Labels section, remove the check mark next to All Mail and Important so that those labels will not show in IMAP
I recommend performing the five swipe gesture to reset the hub after completing the above steps. Be aware it might take a bit for the settings to sync between the server and your device. To avoid a delay when deleting on your BlackBerry 10 device, simply tap on the three dots (overflow menu), and tap on Refresh to make sure everything syncs up properly.
These steps solved my issue and not one message has wound up in the All Mail / Archive folder since modifying those settings. For more information you can check out the Google IMAP advanced control instructions and the forums threads below (of which they are several devoted to this). If, for any reason, you wish to return to the default settings, all of the above steps are reversible.
If you need further help setting up Gmail on your BlackBerry 10 device using IMAP, CalDev or CardDev, be sure to check out Adam's tutorial here.
Please note that by performing the above actions, if you have your Gmail account added to any legacy BBOS smartphone, it will essentially prevent you from sending or receiving mail on that device and cease syncing with the account. I received a notification from BIS alerting me that the All Mail folder is required in order to function properly.
Read the getting email to delete forum thread
Read the email deletion / hub email options forum thread