? tab(-10, AG_RESETWINDOW); chr(127);

The function AG_RESETWINDOW (16) resets the window to the colors, size, font, and other parameters according to the current settings file.

See the –o parameter command line parameter in the A-Shell Setup Guide for details on specifying a settings file. Also see MX_SHOWWINDOW, which offers another way of doing the same thing (in addition to querying and setting various window characteristics).