When we shrink the browser, the watermark textbox and search button stay the same size because their Grid container columns are a fixed width.

当我们缩小浏览器尺寸时，带水印的文本框和搜索按钮会保持同样的尺寸，因为其grid容器列的宽度是固定的。

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The typical purpose of a watermark is to provide more information to the user about the TextBox itself without cluttering up the rest of the page.

通常用于告诉用户文本框的一些信息而不用页面的其他地方。

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