On e21.5 with efl 18.4 I can not edit the forecast code entry to change it. I asked in IRC channel yesterday about this but no response in the time I had available. Latter I grepped e21 module code looking for e_widget_entry_add . This lead to an easy fix, change line 112 of forecast/src/e_mod_config.c
ob = e_widget_entry_add(evas, &cfdata->code, NULL, NULL, NULL);
ob = e_widget_entry_add(cfd->dia->win, &cfdata->code, NULL, NULL, NULL);
Essentially the same fix as in e_entry -> elm_entry conversion .
Other modules may also be effected, I only looked at forecast.