Thanks muchly Mikeone: I did "Go to App Settings > Message list > scroll down to option "Select 'All' means" > choose "Loaded messages" (instead of "Visible messages")" and then I pressed Select all and the vertical menu appeared with 25 at the top. I press the trashcan and it deletes 25. How to change the 25 to all?
Kerry
25 is the default setting for how many messages the app will sync.
You can extend this amount up to 5000 in the Account settings:
Go to the app's main window (account list view) > long press on Account name > Options and folders > Account options > 'Messages to sync" > choose "5000 messages"
Go back to account list view > tap on the wheel right of the respective Account name. This will force an account refresh.
Be aware that deleting "all selected messages" really means > delete "ALL (selected) downloaded / synced messages" even those (selected) messages which are not visible.
I strongly recommend to set the option "Messages to sync" afterwards back to a reasonable amount like 50 or100, but not much higher.
> Kostya has explained it already several times in detail.