In file_browse_invoke, if the path is blank we attempt to use BKE_appdir_folder_default_or_root to get the user's normal document root. However we are not ensuring that the directory path has a trailing slash, which can result in it being misinterpreted as a file path instead, separating out the last path part. This PR only adds a call to BLI_path_slash_ensure. Pull Request: https://projects.blender.org/blender/blender/pulls/123504