fix a bug with the <c-w>o mapping

now we dont assume the cursor is in the nerd tree window when calling
s:SaveScreenState()

doc/NERD_tree.txt

@@ -889,6 +889,9 @@ fridge for later ;)
 ==============================================================================
 7. Changelog                                               *NERDTreeChangelog*
 
+2.x.x
+    - fix a bug where the <c-w>o mapping  would cause the tree window to be
+      incorrectly sized when reopened.
 2.13.0
     - make NERDTreeChDir option default to 0 (i.e. never change vims current
       working dir by default)

plugin/NERD_tree.vim

@@ -146,7 +146,7 @@ command! -n=1 -complete=customlist,s:CompleteBookmarks NERDTreeFromBookmark call
 " SECTION: Auto commands {{{1
 "============================================================
 "Save the cursor position whenever we close the nerd tree
-exec "autocmd BufWinLeave *". s:NERDTreeWinName ."* :call <SID>SaveScreenState()"
+exec "autocmd BufWinLeave *". s:NERDTreeWinName ." call <SID>SaveScreenState()"
 "cache bookmarks when vim loads
 autocmd VimEnter * call s:oBookmark.CacheBookmarks(0)
 
@@ -2621,12 +2621,13 @@ endfunction
 "FUNCTION: s:SaveScreenState() {{{2
 "Saves the current cursor position in the current buffer and the window
 "scroll position
-"
-"Assumes the cursor is in the NERDTree window
 function! s:SaveScreenState()
+    let win = winnr()
+    call s:PutCursorInTreeWin()
     let t:NERDTreeOldPos = getpos(".")
     let t:NERDTreeOldTopLine = line("w0")
     let t:NERDTreeOldWindowSize = s:ShouldSplitVertically() ? winwidth("") : winheight("")
+    exec win . "wincmd w"
 endfunction
 
 "FUNCTION: s:SetupSyntaxHighlighting() {{{2