I realized that the event handlers that i was setting when creating the
tags input and the multi-select controls were not removed just because
these elements are no longer in the document, and kept firing again and
again.
I no longer can use an anonymous function, because removeEventListener
would not match it with the one passed to addEventListener. I also have
to bind the handler to `this` in order to keep having access to the
object, and, again, can not do it in the call to addEventListener, or
i would get a different function each time.
I added the check to see if the element is connected inside the
connectedCallback because the documentation warns that this callback
“may be called once your element is no longer connected”[0], and i
understood it to mean that the connected and disconnected callbacks
could be called our of order, thus it would be possible to add event
listeners that would not be removed—again.
I am not actually sure where i have to do the same for the rest of the
“internal” events.
[0]: https://developer.mozilla.org/en-US/docs/Web/Web_Components/Using_custom_elements#using_the_lifecycle_callbacks