kmail: automatically show attachements

I recently found a nice feature in kmail. In the menu 'view' > attachement there was the choice between 'smart', 'always show attachments inline' etc.

I am quoting from memory, because this option has suddenly disappeared. I used it no later than yesterday. Today, I went to the kmail settings to change the layout (message beside the list, instead of underneath) and then I noticed that this option had gone.

I still have another account where the feature is still present. See attached screenshots.