Hi Tobias '''Undo Deletion''' The app gives users the ability to display a confirmation prompt before deletion, rather than an Undo feature. This is enabled from: Settings > General Settings > Interactions: Confirm Actions '''Folder add/delete/rename''' Adding, deleting and renaming folders is not currently supported within the app. This needs to be managed from your email providers web portal or another client. The best way to suggest and show support for new ideas is through [http://example.com Mozilla Connect]. A feature request similar to your own is linked below and open to votes. https://connect.mozilla.org/t5/ideas/add-the-ability-to-create-imap-folders/idi-p/72777