diff --git a/bundle/vim-chat/autoload/chat/windows.vim b/bundle/vim-chat/autoload/chat/windows.vim
index a0eb71c92..dcb9baa2a 100644
--- a/bundle/vim-chat/autoload/chat/windows.vim
+++ b/bundle/vim-chat/autoload/chat/windows.vim
@@ -242,7 +242,7 @@ endfunction
 
 let s:complete_num = 0
 function! s:complete(base,num) abort
-  if a:base =~# '^/[a-z]*$'
+  if a:base =~# '^/[a-z_A-Z]*$'
     let rsl = filter(copy(s:chatting_commands), "v:val =~# a:base .'[^\ .]*'")
     if len(rsl) > 0
       return rsl[a:num % len(rsl)] . ' '