* harbour/src/rtl/gtxwc/gtxwc.c
+ added support for selecting text with mouse and coping it
to clipboard buffer.
By default this functionality is disabled and can be enabled by:
hb_gtInfo( HB_GTI_SELECTCOPY, .t. )
Marked mode is started by LEFT MOUSE button pressed with SHIFT key
and stopped when LEFT MOUSE button is released. Selected text is
highlight in similar way to GTWVT.