gtk:text-view-window (view wtype)

view -- a gtk:text-view widget
wtype -- a gtk:text-window-type value with the window to get

The gdk:window object, or nil.

Retrieves the GDK window corresponding to an area of the text view. Possible windows include the overall widget window, child windows on the left, right, top, bottom, and the window that displays the text buffer. Windows are nil and nonexistent if their width or height is 0, and are nonexistent before the widget has been realized.