The Preferences dialog box's File Types / Editors category defines which external applications to use for various file extensions.
Open in Code View
Specifies the file types to be opened in Dreamweaver's Code view (defaults to .js , .txt , and .asa ).
External Code Editor
Specifies the external text editor optionally used to edit HTML and other code, typically HomeSite (Windows) or BBEdit (Macintosh), which ship with Dreamweaver on their respective platforms. The application chosen here appears in the Edit Edit With... menu command and is accessible using Ctrl+E (Windows) or Cmd+E (Macintosh).
Reload Modified Files
Determines whether to reload a document that has been modified outside of Dreamweaver, usually an image edited in Fireworks or a .swf file edited in Flash. Available options are:
Prompt
Ask the user whether to reload modified files.
Never
Don't reload modified files (and don't prompt the user).
Always
Reload modified files without prompting the user.
Save on Launch
Determines whether to resave a document when an external editor (such as Fireworks, BBEdit, or HomeSite) is launched to manipulate it. Available options are:
Prompt
Ask the user whether to reload modified files.
Never
Don't reload modified files (and don't prompt the user).
Always
Reload modified files without prompting the user.
Extensions list
A list of file types for which to set external editors. Select a file type from the list to set the corresponding external editor in the Editors column. Use the plus (+) and minus (-) buttons to add or remove file types. The most important ones to set are the .png , .gif , .jpg , .jpe , and .jpeg file types, typically edited with Fireworks.
Editors list
A list of external editors for each file extension listed in the Extensions list. Use the plus (+) and minus (-) buttons to add or remove editors from the list. Multiple editors can be specified and the primary editor can be designated by clicking the Make Primary button. The primary and secondary editors appear in the contextual menu. For example, you can right-click (Windows) or Ctrl-click (Macintosh) on a .gif image in the Document window and choose Edit With Fireworks 4 from the contextual menu.