STRINGA_MaxChars, STRINGA_Buffer, STRINGA_UndoBuffer, STRINGA_WorkBuffer
(I) - Specify various buffers defined for string gadgets and extended
string gadgets.  If your value of STRINGA_MaxChars is less than
SG_DEFAULTMAXCHARS (128 for now), then this class can provide all these
buffers for you.  Note that undobuffer and workbuffer can be shared by
many separate gadgets, providing they are as large as the largest maxchars
they will encounter.