>but timer not only timer control , i mean timer and label control , because timer refresh the second time and use label to display
>the current time.
> I also Try setting BackgroundImageLayout to Stretch. this attribute can full screen but the original image will magnify in same time.
>I want to white background and use original size company logo. Why no method can do?

Because that's the way WinForms works. Controls added to the client area of the main form will always have a higher z order than child forms. IAC what is the point of having a label on the client area if most of the time it would be hidden by a child form?

A better design would be arrange the controls so that they will be *docked* in the main form - if they are docked then they will be excluded from the clilent area.....