reflfit is implemented as a GUI layer on top of the underlying mlayer program. For the most part you will never need to access mlayer directly, but there are some features which are not yet implemented in the GUI.
In particular you may need:
ulc - unload constraints
lc - load constraints
You must be sure to use the correct number of parameters for the command, or you will need to exit and restart the program. In practice this means you will need to try them directly in the underlying program before you can use them from the GUI.
The attached pages list all the mlayer commands for completeness, but you will not need most of them, and some of them will cause the link between the GUI and mlayer to fail, so save your state before continuing!
mlayer parameters
mlayer layers
mlayer fit
mlayer io
mlayer display
mlayer plot
Don't try running the movie commands directly, because the command window will timeout before the movie is complete. The Tcl console allows you to program your own movies.