If you are using Horde Webmail to delete mail on the server, these are the steps you will need to take before you can remove mail entirely. By default, Horde does not come with a “Trash” folder so this must be created before you are allowed to delete mail.
1) Login and click on “New Messages”
2) Click on the “Folder Actions” and select “Create Mailbox”
3) Name the new mailbox “Trash”
4) In the same Folder Action dropdown, select “Rebuild folder list”
Next, Go to the Gear Icon in the top menu bar.
Select the link “Deleting and moving messages”
Check the following boxes:
Mark messages as seen when deleting? (Check)
Move deleted messages to your Trash mailbox instead of marking them as deleted in the current mailbox? (Check)
In Trash mailbox dropdown, select “Trash”
Purge Trash how often, select “Daily”
Purge messages in Trash mailbox older than this amount of days
Select your option here. (5)
Now all deleted email will be sent to your trash folder. You can have Horde Delete this automatically if you have a time frame set or you can manually delete them in the interface.