Starts resizing a window. This function is used if an application has window resizing controls. When GDK can support it, the resize will be done using the standard mechanism for the [window manager][gtk-X11-arch] or windowing system. Otherwise, GDK will try to emulate window resizing, potentially not all that well, depending on the windowing system.
position of the resize control
mouse button that initiated the drag
X position where the user clicked to initiate the drag, in root window coordinates
Y position where the user clicked to initiate the drag
timestamp from the click event that initiated the drag