Hello Ronaldo,
Normally we configure the webdynpro component in FPM configuration itself. I don't have much idea about launch_url method.
Whenever you are calling a webdynpro application in FPM(on button action), try to configure the Wed dynpro component as a dialog box in FPM component configuration.
Select the free style uibb and provide the component name and window name in the FPM configuration it self.
Each Page type contains a page id in configuration itself and provide the same while calling the dialog box.Look into the below sample code.
case io_event->mv_event_id.
when cl_fpm_event=>gc_event_button_action.
* Calling webdynpro application on button action
ls_dialog_box_properties-height = '500'.
ls_dialog_box_properties-width = '1000'.
lo_fpm->open_dialog_box(
exporting
iv_dialog_box_id = 'PAGE_1' ----> Dialog box page id
is_dialog_box_properties = ls_dialog_box_properties ).
endcase.
Try to launch your webdynpro application using FPM configuration, you will surely get expand/maximize option.
Regards,
Naga