0 I understand, but it will work only on .NET framework 4.5. How do I made it to work in .NET framework 4.0
0 Check below urls can be helpful to you
http://msdn.microsoft.com/en-us/library/system.windows.controls.spellcheck(v=vs.110).aspx
http://www.codeproject.com/Articles/388912/Spell-Check-Enabled-RichText-Editor-in-WPF