The SelText property returns the text which is currently
selected in the virtual display. If no text has been selected and the
SelLength property is greater than zero, then the text
starting at the position specified by the SelStart property
will be returned.
To read a single character a specific location in the display, it
is preferable to use the Cell property rather than calculating
the offset, setting the SelStart property and then reading the
SelText property.