The File Open dialog Files of type drop down combo-box contains an entry for every document type defined. The excessive number of document type entries can make this combo-box harder to navigate.
Zeus offers two ways to remove unwanted entries from the combo box.
The first is to use Options, Document Types menu and delete any unwanted document types.
The second less drastic measure is to once again use the Options, Document Types menu, but this time edit the unwanted document types and turn off the Display this file type in the file open types list option.