当你正在使用选框工具或自由变换，按住组合键opt + Shift的同时再用鼠标拖动可以从中心按比例对对象进行按比例缩放。

When you are using the Marquee tools or Free Transform, hold down Opt + Shift + drag will scale proportionally from the center.

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例如，能够打开一个组合框，滚动到一个选项，然后拖动选项到一个正在创建的文档中。

For example, being able to open a combo box, scroll to a choice, and then drag the choice onto a document under construction is a very powerful idiom.

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