1929220 - [X11] Dragging and dropping an image or selected text freezes Firefox

Status: RESOLVED DUPLICATE of bug 1917854

(Core :: Widget: Gtk, defect, P2)

Description

[Łukasz]

Attachment: Firefox drag&drop bug.mp4

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0

Steps to reproduce:

1. Launch Troubleshoot Mode.
2. Go to any website, e.g., https://bugzilla.mozilla.org/home.
3. Quickly grab, drag, and drop an image.

I’m using Firefox on Arch Linux with Cinnamon, along with GNOME applications. I’m on X, not Wayland.

Actual results:

4. The entire Firefox browser freezes for up to a minute.
   This is visible in the attached mp4.

The issue also occurs with selected and dragged text.

As shown in the mp4, it can happen on the very first drag of an image.
Sometimes, it happens after more than one drag. It seems there’s a pattern — the drag might need to be over a specific distance or area of the image.
Testing is difficult because Firefox needs to be restarted each time it freezes.

---

Previously, it seemed like my extension was the cause of the issue, and I solved it.
https://bugzilla.mozilla.org/show_bug.cgi?id=1881971

Now the problem has returned with double the intensity.

It happens quite often, unexpectedly. Sometimes, the mouse accidentally releases the Left Mouse Button unintentionally, and Firefox freezes for up to a minute.

Expected results:

4. Firefox should not freeze at all.

Comment 1

[Łukasz]

Attachment: Firefox drag&drop bug text and video.mp4

Comment 2

[Łukasz]

Aha: During this freeze, the video still plays on the page (as shown in the second mp4), as well as in the background or in PiP mode—the video image doesn’t freeze or stutter, and the video runs smoothly.

I suspect there’s an issue with the mouse handling system, causing Firefox to wait for clicks, but the clicks don’t reach Firefox. They are triggered after Firefox unfreezes.