diff --git a/lua/lualine/utils/utils.lua b/lua/lualine/utils/utils.lua
index 3910834..c231955 100644
--- a/lua/lualine/utils/utils.lua
+++ b/lua/lualine/utils/utils.lua
@@ -76,7 +76,7 @@ function M.is_focused()
 end
 
 function M.is_valid_filename(name)
-  local invalid_chars="[^a-zA-Z0-9_. ]"
+  local invalid_chars="[^a-zA-Z0-9_. -]"
   return name:find(invalid_chars) == nil
 end