diff --git a/autoload/nerdtree.vim b/autoload/nerdtree.vim
index b138c21..bdf3deb 100644
--- a/autoload/nerdtree.vim
+++ b/autoload/nerdtree.vim
@@ -61,7 +61,6 @@ endfunction
 function! nerdtree#compareNodesBySortKey(n1, n2)
     let sortKey1 = a:n1.path.getSortKey()
     let sortKey2 = a:n2.path.getSortKey()
-
     let i = 0
     while i < min([len(sortKey1), len(sortKey2)])
         " Compare chunks upto common length.
@@ -73,9 +72,9 @@ function! nerdtree#compareNodesBySortKey(n1, n2)
             elseif sortKey1[i] ># sortKey2[i]
                 return 1
             endif
-        elseif sortKey1[i] == type(0)
+        elseif type(sortKey1[i]) == v:t_number
             return -1
-        elseif sortKey2[i] == type(0)
+        elseif type(sortKey2[i]) == v:t_number
             return 1
         endif
         let i = i + 1
diff --git a/lib/nerdtree/path.vim b/lib/nerdtree/path.vim
index 2d8de23..0aa592e 100644
--- a/lib/nerdtree/path.vim
+++ b/lib/nerdtree/path.vim
@@ -7,10 +7,6 @@
 " ============================================================================
 
 
-" This constant is used throughout this script for sorting purposes.
-let s:NERDTreeSortStarIndex = index(g:NERDTreeSortOrder, '*')
-lockvar s:NERDTreeSortStarIndex
-
 let s:Path = {}
 let g:NERDTreePath = s:Path
 
@@ -374,7 +370,8 @@ function! s:Path.getSortOrderIndex()
         endif
         let i = i + 1
     endwhile
-    return s:NERDTreeSortStarIndex
+
+    return index(g:NERDTreeSortOrder, '*')
 endfunction
 
 " FUNCTION: Path._splitChunks(path) {{{1
@@ -395,7 +392,7 @@ endfunction
 " FUNCTION: Path.getSortKey() {{{1
 " returns a key used in compare function for sorting
 function! s:Path.getSortKey()
-    if !exists("self._sortKey")
+    if !exists("self._sortKey") || g:NERDTreeSortOrder !=# g:NERDTreeOldSortOrder
         let path = self.getLastPathComponent(1)
         if !g:NERDTreeSortHiddenFirst
             let path = substitute(path, '^[._]', '', '')
diff --git a/lib/nerdtree/tree_dir_node.vim b/lib/nerdtree/tree_dir_node.vim
index 03c3545..30db853 100644
--- a/lib/nerdtree/tree_dir_node.vim
+++ b/lib/nerdtree/tree_dir_node.vim
@@ -607,8 +607,12 @@ endfunction
 " FUNCTION: TreeDirNode.sortChildren() {{{1
 " Sort "self.children" by alphabetical order and directory priority.
 function! s:TreeDirNode.sortChildren()
+    if count(g:NERDTreeSortOrder, '*') < 1
+        call add(g:NERDTreeSortOrder, '*')
+    endif
     let CompareFunc = function("nerdtree#compareNodesBySortKey")
     call sort(self.children, CompareFunc)
+    let g:NERDTreeOldSortOrder = g:NERDTreeSortOrder
 endfunction
 
 " FUNCTION: TreeDirNode.toggleOpen([options]) {{{1
diff --git a/plugin/NERD_tree.vim b/plugin/NERD_tree.vim
index 35b47c3..71d719a 100644
--- a/plugin/NERD_tree.vim
+++ b/plugin/NERD_tree.vim
@@ -81,12 +81,8 @@ call s:initVariable("g:NERDTreeCascadeSingleChildDir", 1)
 
 if !exists("g:NERDTreeSortOrder")
     let g:NERDTreeSortOrder = ['\/$', '*', '\.swp$',  '\.bak$', '\~$']
-else
-    "if there isnt a * in the sort sequence then add one
-    if count(g:NERDTreeSortOrder, '*') < 1
-        call add(g:NERDTreeSortOrder, '*')
-    endif
 endif
+let g:NERDTreeOldSortOrder = []
 
 call s:initVariable("g:NERDTreeGlyphReadOnly", "RO")