This message is sent after a window has been scaled.
Contains one of the flags from the enumeration window_size.
|Low-order part||The new width (in pixels) of the window.|
|second part||The new height (in pixels) of the window.|
If the window processes this message, it should return zero.
If during the processing of this message, the function set_scroll_position or move_window is called for child windows, the redraw parameter should be set to true.