探究当父窗口隐藏、最小化等情况时，对子窗口的影响，哪些是受父窗口的限制的。windows下的窗体的parent有两种类型：parent、owner，两种情形要分别对待。(To find out the affection to chidren windows when the parent window is hidden or minimized. There are two types of "parent" window conception in windows programming:"parent" and "owner". Each should be tested separately.)