mono/xwt — pull request #92 by luiscubal (2012-03-29 21:00:57+00:00)
Title: [WPF] Fix NRE in MenuItemBackend when instance is separator

Fixed WPF MenuItemBackend that triggered an exception is EnableEvent/DisableEvent when menuItem was null(which happened in the separator backend).

This prevented the buttons sample from running properly.

I'm not 100% sure this is the best possible solution, but it does seem to work for now.