Ok, so it's simple,
If you want to edit all the members, you have to activate the Edit factory Mode Scope and have both pencils blue.
Manually:

A code to pass from Member scope to Factory Scope is and vice versa is:
- To change the active edit scope to edit member scope, depending on the needs, use:
ThisDoc.Document.ComponentDefinition.ModelStates.MemberEditScope = MemberEditScopeEnum.kEditActiveMember
or:
oDoc.ComponentDefinition.ModelStates.MemberEditScope = MemberEditScopeEnum.kEditActiveMember
- To change the active edit scope to edit factory scope, depending on the needs, use:
ThisDoc.Document.ComponentDefinition.ModelStates.MemberEditScope = MemberEditScopeEnum.kEditAllMembers
or:
oDoc.ComponentDefinition.ModelStates.MemberEditScope = MemberEditScopeEnum.kEditAllMembers
CCarreiras