In C# mode, if there are spaces before "#region" or "#endregion", wisent-csharp can not parse correctly¡£
This bug can be fixed like this:(wisent-csharp.el)

(define-lex-regex-analyzer wisent-csharp-lex-ignore-region
  "Ignore # type macros for C sharp."
  (goto-char (match-end 0))
  (forward-word 1)
  (setq semantic-lex-end-point (point))
(define-lex-regex-analyzer wisent-csharp-lex-ignore-endregion
  "Ignore # type macros for C sharp."
  (setq semantic-lex-end-point (match-end 0))

After replacing the code above, go into the contrib directory and type "make" to recompile wisent-csharp.el.