Unable to delete VDOM with zero references

Hello,

I’d like to know if any of you have ever had this problem:
As per title, I’m trying to remove a VDOM ,and the "delete" button is obscured.

I deleted all references and now I see "zero" in the reference column, but the button does not activate 

I tried to move the interfaces to vdom root and here I have a problem: I had created a tunnel interface and I cannot move it to the vdom root.. I get the following error: "Attribute 'interface' MUST be set."

even on this interface there are no references.

Could it be a bug or something?
The OS version is 7.0.3

Someone can help me figure out where I’m going wrong, please?

Thank you.