I found something.
"Button Setup" is not "Button Setup...", it is immediately applied when select the menu (and object name disappear). You need to "undo" to cancel it.
Help saying "No action" as "You can also choose this option to disable a button", but it seems there is no way to disable a button other than "ungroup" the button.
You can see the object name with ungrouping the button.
"Go to object" is not working as you say, this should be a bug. (I like to say it's a bug)
When button setting is done in a field, GroupButton is made.
Please imagine by which a different object can make sure that an object in a field will be wrapped.
"Ungroup" to release this.
Even if "No action" is chosen, the GroupButton attribute is left.
<Object type="GroupButton" name="b" > <GroupButtonObj> <Object type="Field" name="a"> <FieldObj> </FieldObj> </Object> </GroupButtonObj> </Object>
Ungroup did the trick. Strange how this behaves differently from 13.