public void add_child_in_window (Widget child, TextWindowType which_window, int xpos, int ypos)
Adds a child at fixed coordinates in one of the text widget's windows.
The window must have nonzero size (see set_border_window_size). Note that the child coordinates are given relative to scrolling. When placing a child in WIDGET, scrolling is irrelevant, the child floats above all scrollable areas. But when placing a child in one of the scrollable windows (border windows or text window) it will move with the scrolling as needed.
which window the child should appear in
X position of child in window coordinates
Y position of child in window coordinates