Hi guys.
I have a solution running on DW 9.8.
I have set up an ItemType that inherits another ItemType. Let's call my ItemType "Banner" and the ParentItemType "Section".
"Banner" inherits "Section".
"Section" has a Group and an ItemTab field.
"Banner has another ItemTab field.
I am using Banner in an ItemRelation field on another Item.
When I click on "Add Banner" on the ItemRelationList, the modal dialog displays the content of the Banner ItemType.
In the screenshots attached, you can see that the ItemTab that is inherited is displayed right (interfaceIssue2.png) while the ItemTab defined on the ItemType it is not (interfaceIssue1.png).
I believe this is an interface bug. Maybe you can look into it.
I have experienced the same behavior even when using an ItemType field.
Thank you,
Adrian