diff --git a/plugin/gundo.vim b/plugin/gundo.vim
index 2f06df3..c6a7c37 100644
--- a/plugin/gundo.vim
+++ b/plugin/gundo.vim
@@ -140,6 +140,7 @@ function! s:GundoMarkPreviewBuffer()
     setlocal nonumber
     setlocal norelativenumber
     setlocal nowrap
+    setlocal foldlevel=20
     " TODO: Set foldmethod?
 endfunction