Should a popover include an arrow or not?

I'm trying to decide if popover panels should include an arrow pointing to the component that triggered it, or if this is an unnecessary element.

Others' Approach

Here are some of my research on this topic:

"A popover includes an arrow pointing to the location from which it emerged." documented from Apple Human Interface Guidelines

Old version of facebook's dialogs:

Arrow was attached in all the dialog to strengthen the association between the trigger and the dialog.

enter image description here

New version of facebook's dialogs:

Arrow is taken away. Highlight the appearance of the icon if the associated dialog is opened.

enter image description here

My Opinion

An arrow helps users to get understand the location from where the popover is coming, and the element that triggers the popover. Especially there are mutiple triggers (like above facebook example), an arrow additionally helps users distingush between the association easily.

Like this below example, if the content text of the tooltip is too long, it possibly would misunderstand users that the tooltip indicates the item next to the trigger itself at first glance.

enter image description here

My opinion is if there is only one trigger element, then a popover without arrow is appropriate.

And vice versa, if there are more than one trigger element that would pop up a dialog or popover or tooltip, then attaching an arrow would be better.

Is this correct?

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