Lowers this to the bottom of the Z-order (stacking order), so that other windows with the same parent window appear above this.
This is true whether or not the other windows are visible.
If this is a toplevel, the window manager may choose to deny the request to move the window in the Z-order, lower only requests the restack, does not guarantee it.
Note that show raises the window again, so don’t call this function before show. (Try show_unraised.)
| this |
a Window |