Select something in this document, like this:
The `args.SelectedText` is "Ð¡Êó"
But if you use Crtl + C to copy it out，the result is correct.（"小鼠"）
And there also some problems in text selection. You can select a half character:
If your selection begins with the half character, the whole sentence will go wrong.
I use these code to fix encoding bug:
Encoding gbEncoding = Encoding.GetEncoding("GB2312");
Encoding isoEncoding = Encoding.GetEncoding("ISO-8859-1");
byte byteString = isoEncoding.GetBytes(args.SelectedText);
string result = gbEncoding.GetString(byteString);