diff --git a/lib/nerdtree/path.vim b/lib/nerdtree/path.vim
index 5de1dfe..4cdf1a3 100644
--- a/lib/nerdtree/path.vim
+++ b/lib/nerdtree/path.vim
@@ -658,6 +658,7 @@ function! s:Path._strForEdit()
     "return a relative path if we can
     let isRelative = 0
     if nerdtree#runningWindows()
+        let p = self.str()
         let isRelative = stridx(tolower(p), tolower(cwd)) == 0
     else
         let isRelative = stridx(p, cwd) == 0