Start Firefox in <u>Safe Mode</u> to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if <u>hardware acceleration</u> is causing the problem. *switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes *do NOT click the "Refresh Firefox" button on the Safe Mode start window *https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode *https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems ---- Firefox will detect if your computer’s memory is running low, which is defined as lower than 400MB, and suspend unused tabs that you haven’t used or looked at in a while. The new tab unload feature is controlled on the about:config page with a preference that you can set to false to disable this feature. Keep in mind that this makes you vulnerable to low memory issues. *browser.tabs.unloadOnLowMemory = false You can open the <b>about:config</b> page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue. *https://support.mozilla.org/en-US/kb/about-config-editor-firefox <hr> *http://www.ghacks.net/2019/03/01/firefox-67-automatically-unload-unused-tabs-to-improve-memory/ *https://blog.mozilla.org/blog/2019/05/21/latest-firefox-release-is-faster-than-ever/

Thanks for the reply, but that's not really the problem. I did try what you suggest, but still the tab isn't loading fully in the background. For example, scripts on the background tab don't run until the tab is selected. So what I need is to fool the tab into thinking it has focus. I've looked through the config to see if there is a switch in there, but nothing stands out. Thanks Mr M