Recommended 

hm: 

If the user has opened the application without supplying a file name argument, the Open dialog box should use the user's home directory as the default directory. 

An exception to this rule might be made if a clearly more useful directory can be identified; for example, the icon editor might default to $HOME/.dt/icons. For applications that allow editing, never default to a directory in which the user does not have read and write permission, such as /usr/dt/bin. 

Required 

hn: 

If the user has opened the application with a file name argument, the Open dialog box should default to the directory in which that file resides.