Generic function
Returns the text cursor associated with the specified sheet.
sheet-text-cursor sheet => text-cursor
<sheet>.
false-or(<cursor>).
duim-sheets
duim-sheets
Returns the text cursor associated with sheet. The text cursor associated with a sheet is distinct from the pointer cursor associated with the same sheet: the pointer cursor represents the current position of the pointer associated with the attached pointer device, while the text cursor represents the position in the sheet that any text typed using the keyboard will be added. Only those sheets that contain children that allow some form of text-based input have an associated text cursor.