firefox does not detect mousemove events

[Georges Varouchas]

I have an issue, which I saw only on Firefox : after some time (or some event which I haven't identified yet), Firefox does not react to my mouse movement events

meaning :

  * when hovering over an HTML item, it does not highlight/change appearance even if it is supposed to do so,
  * when hovering over a clickable item, the cursor does not change,
  * when hovering over selectable text, the cursor does not change,
  * tooltips do not appear,
  * etc ...

if I trigger other GUI events (if I *click*, or if I *press any keyboard key* -- `[A]`, `[Shift]`, `[Ctrl]` ...), then the GUI reacts (cursor changes, tooltips appear, animations get triggered ...), a bit as if, by handling that other event, firefox realized "oh, the cursor is actually there", but with no external event, my mousenter/mouseleave events seem to be ignored, or stalled.

Running Ubuntu 22.10 (kinetic), and regular firefox snap install (my current version: 109.0.1-1).

As said in the previous sentence: firefox is installed through snap (which, if I am correct, is the default way to install firefox on a Ubuntu system these days) not through an apt package.

Is this a known issue ?

[Georges Varouchas (gvarouchas)]

firefox is installed through snap, not apt

[Georges Varouchas (gvarouchas)]

I reported the same issue in the form of a question on askubuntu.com :

https://askubuntu.com/questions/1448645/mouse-hover-events-broken-on-firefox

apparently some other users experience the same issue

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Ivan Goshevski (igoshevski)]

What triggers this issue is moving the focus away from Firefox. I do a lot of alt+tab and the issue appears after several of them. Then I need to close Firefox and start again to fix the issue.

Others have pointed out that this is Firefox issue with Wayland. Even those that have installed Firefox using apt have experienced the same.

[Georges Varouchas (gvarouchas)]

Someone pointed me to a comment on bugzilla:

* [someone's answer on askubuntu.com](https://askubuntu.com/a/1455694/18501)
* [the comment to issue 1774531 on bugzilla](https://bugzilla.mozilla.org/show_bug.cgi?id=1774531#c25)

This comment indicates to set `MOZ_ENABLE_WAYLAND=1` in your `~/.profile` to force Firefox to use Wayland.

With this environment variable on, the issue does not appear anymore.

Also worth noting: a comment (commenter @aeno still on [my askubuntu.com question](https://askubuntu.com/a/1455694)) mentions that he/she experiences the issue on ArchLinux (with Wayland).

It looks like this issue is not Ubuntu specific.