When creating custom Template through "Event Actions > Add Template", user is not enforced to define Category and Type of an Attribute block, which in turn throws errors in an attempt to populate event.
This succeeds:


But when using the template, obviously it turns red:

Hence suggestion is to enforce user to define Attribute Category and Type when creating Template.
When creating custom Template through "Event Actions > Add Template", user is not enforced to define Category and Type of an Attribute block, which in turn throws errors in an attempt to populate event.
This succeeds:

But when using the template, obviously it turns red:

Hence suggestion is to enforce user to define Attribute Category and Type when creating Template.