gdk:window-begin-resize-drag-for-device (window edge device button xroot yroot timestamp)

window -- a toplevel gdk:window object
edge -- a gdk:window-edge value with the edge or corner from which the drag is started
device -- a gdk:device object used for the operation
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, use the gdk:event-time function

Begins a window resize operation for a toplevel window. You might use this function to implement a "window resize grip", for example. In fact gtk:statusbar widgets uses it. The function works best with window managers that support the Extended Window Manager Hints, but has a fallback implementation for other window managers.