I can't find the reset bounding box option, thing that I was able to do in the previous versions of Illustrator when building an arrow head. I am not looking for a different method on how to make an arrow head but only to understand why I'm not able to see the reset bounding box option.
In a nutshell:
after building a square and rotating it by 45˚ I was right clicking on the square and clicking on the reset bounding box option.
I was using this method so I could scale relative the rotated square shape on a vertical axis. The reset bounding box appears only if I move one of the anchor points.
I hope this is clear enough, if not let me know if you need any other information.