Firefox Quantum, that changed the Firefox browser UI, improved speed and the animations you see when you bookmark and when the page loads are all part of it and these are not new to Quantum users, we’re reminding this because the time has passed so quickly after Firefox 57 launch that Firefox 59 has been released recently.
The news is Mozilla is currently working to fix performance issues caused by Tab Throbber on Mac OS. The company now temporarily offers a Nightly-only-run time preference to deactivate it.
Disable Tab Throbber in Firefox Quantum
If you’re using Nightly and don’t like the Tab Throbber loading,
1. Visit about:config
2. Create a new Boolean preference named browser.tabs.hideThrobber and set it value to true.
Tab throbber won’t be loaded.
Mozilla which is working on below bugs caused by Tab Throbber, confirms the preference won’t get into release channel.
You may like to read the following articles related to Firefox 61 (which is currently on Nightly)