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When you try to use surrogate pair characters in a ListView control in Microsoft Office Visio 2007 or in Microsoft Office Visio 2003, the characters are not displayed correctly. The characters appear as square rectangles.
For example, when you paste surrogate pair characters in the Label box in the Define Custom Properties dialog box for a shape in your drawing (right-click the shape, click Properties, and then click Define), the surrogate pair characters are displayed as square boxes in the Label column of the Properties box.
This problem occurs because the ListView control in Visio does not currently support surrogate pair characters.
To work around this problem, do not use surrogate pair characters in ListView controls in Visio.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
A surrogate pair is a pair of 16-bit Unicode code values that represent a single character. The first (high) surrogate is a 16-bit code value in the range U+D800 to U+DBFF. The second (low) surrogate is a 16-bit code value in the range U+DC00 to U+DFFF. Surrogate pairs extend the character set beyond the Unicode character. By using surrogates pairs, Unicode can support over one million characters. For more information about surrogate pairs, visit the following Microsoft Web site: