Drag a textfile onto the iconbar icon and it
will be displayed in an editor window. Subsequent
dragging of a Lua file (or a text file with first
line #! lua) will run the program with the textfile's
pathname as a commandline argument; standard output
will appear in a taskwindow.

Click Select on the iconbar icon to redisplay the textfile.
Click Adjust on the iconbar icon to unload the textfile.