Purpose With SaveControl you can save the state of a control as a file. 
Example SaveControl  name="rtf1"  toFile="C:\temp\rtf.tsm"

The status of the control created with name "rtf1" is stored into the given file.

Format SaveControl  name="name"  toFile"filename"

The command is possible for ActiveX controls that support the "IPersistStreamInit" interface.

In the Control command you may restore the status of the control from the file via the option loadFromFile=.

For testing purposes Microsoft's "ActiveX Control Test Container" TSTCON.EXE can be used. Apply the menu option "Edit -> Insert control from stream" in order to create the control from the file generated with SaveControl.

Components GuiXT + Controls