Solution : https://service.sap.com/sap/support/notes/569472 (SAP Service marketplace login required)
Key words :
start transaction se80select bsp-application, edit modeactivate page <%@page language=, newly received page visible, url = exit_url = request->get_header_field, make received pages visible, return } var newshowframe = gethiddenframe, newly received page, %><html><script language=, standard error page, double buffering technique