Currently, if you preview a record from the main view for contacts, companies, etc. and then go into “Actions” menu within the preview window, “Delete” is not an option. You have to navigate to the full record view via the “View record” button in the preview. Then from the full record view, the “Actions” menu will show option to delete.
Please provide either “Delete” from record previews as generally available Actions option, or at minimum provide an settings option to enable “Delete” from record previews.