Wrong display of icons at medium/large/extra large size in File Manage

I did file association by referring codes from C# FileAssociation Class - CodeProject (http://www.codeproject.com/Articles/43675/C-FileAssociation-Class). It works roughly well as expected: . Double clicking a file with extension association will launch the appropriate program. . While setting icon view of File Manager as "Small Icon", the file's icons show correctly. But if I set icon view...