The display of objects within a container can be affected by a number of factors. Zooming, scrolling, updating and resetting all affect the display. For more information on handling zooming and scrolling, refer to Container Scaling Values and Container Offsets.
When updating the display of objects within a container, the entire client area of the window that owns the container can be updated, or just a small portion of the client area can be updated. L_ContainerUpdate updates all or part of the client area of the window that owns the container based on the parameters passed to it.
The display of objects within a container can also be reset. This removes all objects within the container from the drawing displayed on the screen. This function does not remove the objects from the container, it just removes them from the display.