Common Desktop Environment: Style Guide and Certification Checklist

Attachment Functionality

To incorporate attachments into an application, several issues should be considered.

What Can Be Attached?

You should determine for each application what items it can attach. For example, Mailer can attach documents, scripts, and applications, but not folders.

What is the Method for Attaching?

There are two methods of attachment, through the file selection dialog box that comes up when you choose Add File from the Attachment menu, and through drag and drop from File Manager or another application.



Drag and drop should not be the only method for attaching objects. 



When the user chooses something to attach from the file selection dialog box that is not an attachable item, then the user receives an error message explaining why the chosen item cannot be attached. For example: 

The folder "My.Stuff" cannot be attached because it is a folder. Only documents, applications, and scripts can be attached. 



When the user attempts to drop something into the attachment list that is not attachable, then the drop fails and the item is snapped back to its source. 

What Happens When Something Is Attached?

The act of attaching document A to document B copies the bits of document A into document B. There is no further connection with the original file. If the user opens the attached document and makes changes, the changes are saved back to the attached document only, not back to a file in the file system.

Attachments in Attachments

Users can attach messages or text files that have attachments inside them. This is sometimes referred to as "nesting". The user reading the text file would perhaps see a mail message icon that the user could then open, which may have a text message and more attachments.