Setting A Top Level Layout
The form's top level layout can be set by clearing the slection (click the left mouse button on the form itself) and applying a layout. A top level layout is necessary to ensure that your widgets will resize correctly when its window is resized. To check if you have set a top level layout, preview your widget and attempt to resize the window by dragging the size grip.
这个我倒是看了,但是具体操作不清楚,望大师指导。