gdk:window-begin-move-drag (window button xroot yroot timestamp)

window -- a toplevel gdk:window object
button -- an integer with the button being used to drag
xroot -- an integer with the root window x coordinate of mouse click that began the drag
yroot -- an integer with the root window y coordinate of mouse click that began the drag
timestamp -- an unsigned integer with the timestamp of mouse click that began the drag

Begins a window move operation for a toplevel window. This function assumes that the drag is controlled by the client pointer device, use the gdk:window-begin-move-drag-for-device function to begin a drag with a different device.