Editing
To edit an item select it in the file type listing and then press the "Edit" button, select "Edit" from the "Actions" menu or right-click on the file type listing and select "Edit" from the popup menu. In the window that appears you can make changes to the item. Fields that need to have a value set will appear in bold.
Note that some items can not be edited, the "Edit" option will be disabled in this case. Also note that there is no way to undo any changes you make, they will take effect immediately when you press the "OK" or "Apply" button.
File Types
The image below shows the "Edit" dialog when editing a file type:

Below is an explanation of the different values you can edit:
- Name: the user-readable name of the file type, the name under wich the file type appears in Windows Explorer.
- Internal Name: the internal identifier of the file type. This value can not be changed.
- Default Icon: the path and number of the default icon that is displayed for the file type.
- to browse for an icon file and select the icon from a list click the "Edit..." button.
- the path does not have to be fully qualified, for example "shell32.dll,2" would select the third icon inside the file "shell32.dll" that must be located somewhere within the %PATH% environment.
- CLSID: the CLSID used for the file type.
- click on the "Generate" button to generate a new CLSID.
- Flags: the value displayed here is a combination of special flags assigned to the file type.
- you can view/edit the individual flags that are applied by pressing the "Edit..." button.
File Extensions
The image below shows the "Edit" dialog when editing a file extension:

Below is an explanation of the different values you can edit:
- Extension: the extension you are editing. This value can not be changed.
- Associated With: the file type the extension is associated with.
- click the "Change" button to select a different file type.
- Content Type: the MIME Content Type of the extension.
- the MIME Content Type of the extension will be set to whatever you enter here. Note that this will not actually create a new MIME Content Type. Use the "MIME Content Type" tool to create a new MIME Content Type.
- Info Tip: text that is displayed in an info tip when you hover your mouse over a file with the given extension in Windows Explorer.
Actions
The image below shows the "Edit" dialog when editing an action:

Below is an explanation of the different values you can edit:
- Name: the name of the action. The name appears in the context menu when you right-click on a file in Windows Explorer.
- File Type Manager builds the internal action name by replacing spaces in the name with underscores.
- Command: the command that is executed when the action is selected.
- Uses DDE (Direct Data Exchange): if the action uses DDE this checkbox is selected.
- DDE is a Windows feature that allows applications to exchange information. If you let an action use DDE it will send the specified DDE message to the specified application when the action is selected.
- DDE specific options:
- Message: the DDE message to send.
- Application: the application the message should be sent to.
- Application (Not Running): the application to receive the message if the previous one is not running or not available.
- Topic: the topic of the DDE message.
Shell Extensions
The image below shows the "Edit" dialog when editing a shell extension:

Below is an explanation of the different values you can edit:
- Name: the name of the shell extension.
- the name is not used anywhere within the normal user interface (ie: Windows Explorer) but is useful to programs like File Type Manager.
- Internal Name: the internal name of the shell extension. This value can not be changed.
- Inproc Server 32: the 32-bit inprocess server DLL used for the shell extension.
- the inprocess server is a special program that will be loaded into the Windows user interface by Windows Explorer and implements the shell extension.
- CLSID: the CLSID of the shell extension. This value can not be changed.
- click the "Query" button to find out more about the CLSID using the "CLSID Tool".
- Threading Model: the threading model used for the shell extension.
- normally shell extensions use "Apartment" threading.
- the "Both" value indicates a shell extension supports both threading models (I think).
- Extension Type: the type of the shell extension.
- Property Sheet Handler: this adds an additional sheet (tab) to file type property dialogs.
- Context Menu Handler: this adds an additional menu item to right-click context menus.
- Copy Hook Handler: this extension hooks into a copy operation when it is performed on the associated file type.
- Drag-Drop Handler: this extension hooks into a drag-drop operation when it is performed on the associated file type.
- Data Handler: not sure what this type does.
- Drop Handler: not sure what this type does.
- Icon Handler: this extension displays a custom icon for a file type (ie: a thumbnail for an image).
- Column Handler: this extension adds an additional column to a folder's detailed view.
- Approved: when this is selected a shell extension is approved to be used on a system.
- if this is not selected a shell extension will not be loaded.
- this only takes effect on Windows NT/2000/XP.