1479711 - TypeError: event.originalTarget.getAttribute is not a function

Status: NEW

(Firefox :: Tabbed Browser, defect, P3)

Description

[Florian Quèze [:florian]]

This bug was automatically filed from Sentry: https://sentry.prod.mozaws.net/operations/nightly-js-errors/issues/3164114/

TypeError: event.originalTarget.getAttribute is not a function
    at onxbldragover(chrome://browser/content/tabbrowser.xml:1254:30)


I just saw this error on Mac, and noticed that it also exists on Sentry from Windows users.

Steps to reproduce:
- open enough tabs to make the tab bar overflow.
- drag a tab to reorder it.
- the JS error appears in the console each time a new tab is hovered with the dragged tab.

The error is on this line: https://searchfox.org/mozilla-central/rev/033d45ca70ff32acf04286244644d19308c359d5/browser/base/content/tabbrowser.xml#1266

I think it would be fine to just silence it with a null check.

Comment 1

[Dão Gottwald [:dao]]

I can't reproduce this on Windows or Linux.

I'd like to understand what's going on here rather than silencing the error. A dragover event with no event.originalTarget or one that doesn't have getAttribute sounds quite broken.