Use the DEFF command to open the External Form Designer, or to open the designer with a specific file.
filename.rff
Specifies the name of the external form file.
MODAL
Launches an external form in the designer from a command block, command file, or EEP. The External Form Designer must be closed in order to continue the next command. Specifying a new file name will create a new external form.
Example
The following command launches the TileMenu_Sample external form within the External Form Designer.
DEFF TileMenu_Sample.rff MODAL
