the total width occupied by its descendant windows.
If a window's pixel width is not an integral multiple of its frame's
-character width, the number of lines occupied by the window is rounded
+character width, the number of columns occupied by the window is rounded
internally. This is done in a way such that, if the window is a parent
window, the sum of the total widths of all its children internally
equals the total width of their parent. This means that although two