Word 2010 does not support Window.Hwnd used in WordViewProvider.cs

[esbenvl]

Thank you for this great project!

I am currently working on a word addin using vstocontrib, visual studio 2013, and word 2010.

I get the error 'Microsoft.Office.Interop.Word.Window' does not contain a definition for 'Hwnd' when trying to compile (at line 44).

Line 43: //Check if we have this window registered
Line 44: if (documents[doc].Any(window => window.Hwnd == wn.Hwnd)) return;

As far as I can see in the microsoft documentation the proberty Hwnd is only supported in word 2013: http://msdn.microsoft.com/en-us/library/office/jj231484%28v=office.15%29.aspx