XmTextSetTopCharacter sets the position of the text at the top
of the Text widget.
If the XmNeditMode is XmMULTI_LINE_EDIT, the line of text
that contains top_character is displayed at the top of the widget
without the text shifting left or right.
If the edit mode is XmSINGLE_LINE_EDIT, the text moves horizontally
so that top_character is the first character displayed.
widget
Specifies the Text widget ID
top_character
Specifies the position in the text to display at the top of the widget.
This is an integer number of characters from the beginning of the text
buffer. The first character position is 0 (zero).
For a complete definition of Text and its associated resources, see
XmText(3).