NB: More recent documentation for Dyalog APL is available at https://docs.dyalog.com/20.0/.
ClassicMode
This parameter specifies whether or not the Session operates in Dyalog Classic mode . The default is 0. If this parameter is set to 1, the Editor and Tracer behave in a manner that is consistent with earlier versions of Dyalog APL.
Note that in this mode, a maximum of 50 Trace windows may be displayed.
See also Classic Dyalog mode.