Bug of MenuManager after renaming a template and clicking "Apply"

[Augustas]

In MenuManager v1.5:

1. I create a new Menu template with the name "menu tpl1", write some content and click SUBMIT
2. I open again this menu template for editing
3. I change the name into "menu tpl2" and click APPLY. Page succesfully reloads.
4. Now I click SUBMIT.
5!! I get template editing form again and this message above the buttons:
--Add Me - module:MenuManager string:templateexists--
I am not able to execute SUBMIT, unless I change the name back into


To summarize, it seems that after changing the template name and hitting "APPLY" user gets a form for submiting a NEW template, that's why the message "template exists" pops up when trying SUBMIT.