Not able to set Default View

[Madhu Mullangi]

I have different views for Different structures. I want to set the default view based on the structure requirements.
To achieve that I only associated one view ( which I wanted ) to the structure. Still I am not getting it as a default view.
I tried to edit the Default view option but I am unable to do that.
How to edit the Default View ?
Attached screenshot for your reference. Guide me if I am in the wrong place to edit Default  view