This can sometimes occur when the default wrapper prevents the arrow icon from displaying. To resolve the situation, remove the following parameter from the URL:

&user_wrapper=user_wrapper

Example:
Original URL that does not show the arrow icon:
https://secure3.convio.net/siteshortname/admin/PageBuilderAdmin?popup_wrapper=&show_empty_components=true&pagebuilder=configure_layout&action=&user_wrapper=user_wrapper&custom_header=configure_layout_header&version_id=xxxx&mfc_pref=T&origin_page=page_manage&show_escaped_html=false&page_id=xxxx

Modified URL that will show the arrow icon:
https://secure3.convio.net/siteshortname/admin/PageBuilderAdmin?popup_wrapper=&show_empty_components=true&pagebuilder=configure_layout&action=&custom_header=configure_layout_header&version_id=xxxx&mfc_pref=T&origin_page=page_manage&show_escaped_html=false&page_id=xxxx