In “View” / “Customize toolbar” , it is clear to me how you ADD a perspective. But how do you DELETE them ?
When you are editing the toolbar, drag the icon off the toolbar.
–edit-- Sorry, misread the question, for the toolbar, yes, wilsonng’s answer is the way to go.
Next to the add-button there is a button which opens a dropdown with more options, including a ‘delete perspective’.
Note: you obviously have to select the perspective you want to delete first.
There is a small bug. If you delete a perspective in the perspective editor, the icon remains in the toolbar. You’ll still have to drag it off the toolbar. The other way is to quit and reopen OmniFocus. The icon will disappear when you restart OmniFocus.
Thank you all, wilsonng answer worked.