Windows Special Characters
The Windows-1252 character set includes several special characters, such as "curly" quotation marks (“, ”, ‘, and ’), the Euro symbol (€), and fancy dashes (– and —). These characters use codes in the range 128 through 159 (hexadecimal 80 through 9F). Some Windows programs insert them automatically when you type a plain quotation mark (" or ') or consecutive dashes (--); you can also insert them by hand using the Alt key and the numeric keypad on your computer.
In the Western European (ISO-8859-1) character set, however, those codes are undefined; and in the Unicode (UTF-8) character set they represent various nonprinting control characters.
If you want to use those characters in your dynamic content, be sure to select the Western European (ISO-8859-1) character set before inserting or pasting them. If you do, you can safely switch to UTF-8 and back without a problem. UTF-8 will display question marks in their places, but they'll look fine when you switch back to ISO-8859-1.
Windows special characters in UTF-8
If the Unicode (UTF-8) character set is selected when you insert or paste those characters into your dynamic content, they are automatically converted to their Unicode equivalents. Those Unicode equivalents are outside the range of the Western European (ISO-8859-1) character set; if you try to switch to ISO-8859-1, you will see an error message.
When you follow the link back to the dynamic content edit area, you can either remove the special characters, select ISO-8859-1, and paste or insert the special characters again; or simply leave UTF-8 as the selected character set.
Summary
If you want to use Windows special characters in dynamic content, make sure the Western European (ISO-8859-1) character set is selected before you insert or paste them into the dynamic content edit area, or don't switch to ISO-8859-1 after the characters are there.