Does it still happen with the flatpak version?

Does it still happen with the flatpak version?

Please explain why that would make a difference.

BTW I originally installed from the Linux Downloads page and allowed it to update since then.

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

• https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Flatpak runs in a sandbox with its own libraries which avoids a lot of variables with different Linux distros.

You can also try disabling Wayland by setting the environment variable MOZ_ENABLE_WAYLAND=0.

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

• https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

I tried these in two ways, in a profile that I use and in a profile that I keep deliberately for testing, that is unmodified and has no extensions or theme. No effect, still a broken cursor.

It's really handicapping my browsing to have lost the ability to see whether something is clickable...

Try installing the xdg-desktop-portal-gtk package.

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

• https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

I’m on Slackware 14.2 with Openbox. Since 14.2 is old I tried a fresh Firefox download in Slackware 15 (running in virtualbox) with no modifications at all. Still a broken cursor.

Does it still happen with the flatpak version?

I installed flatpak (using Virtualbox) in Slackware 15 with Openbox and installed the flatpak version of Firefox. Same broken cursor.