[ solved ] Strange think when editing a related modules in Leads

[rslemer]

In first time, fresh install, if you click in leads, related modules, you can see "Activities"

In layout editor, buttom arrange related list, is possible see a Activities too

But if you removed a relation with Activities and try created again, not is possible anymore

Now, arrange related list buttom, only shows a module "To Do" and when created again, relation is converted to N:N

Before that, some activities not is showed more ...

See attached files