How to set the default button for a form?

如何为一个窗体设置一个默认按钮？

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You can enter the number of seconds, the default button, the caption and the prompt.

你可以输入秒数，缺省按钮，标题和提示。

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If there are no input controls, the initial focus should be assigned to the default button.

如果没有输入控件，初始化的焦点定位将被定位到默认的按钮上。

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While this usually works, Facebook fails to display this virtual menu button for some reason, forcing us to live with the annoying default notification settings.

ENGADGET: Galaxy Nexus HSPA+ review Mobile