Mozilla is currently testing a new feature called "Tab Warming," hoping to improve the experience of tab switching.
According to a new feature description, Tab Warming can monitor a user's mouse cursor and start the "Draw" content when the user hovers the mouse over the label. This way, if a user wants to click and view the tab, and wants to keep a pre-rendered tab, Firefox will do so.
Tab Warming Unlike tag loading and preloading, tags must already be loaded in the browser. This feature only involves "drawing", which is the actual rendering of the page content each time a user switches to a label.
Mike Conley, an engineer at Firefox, said: The program renders and uploads every millisecond, and once the user clicks the mouse, the tab is actually ready. Tab Warming is designed to improve the switching experience between already loaded tags and in some cases may result in the appearance of blank pages or incompletely loaded pages. In most cases, however, it's capable of rendering and uploading layers of most websites quickly, so "in some cases" is negligible.
This feature is currently experimental and can only be deployed on Firefox Nightly. It has no default enablement. Users must load the about: config page in their browser and search for "browser.tabs.remote.warmup.enabled" settings. You can then enable the tab by double-clicking the option and switching its status to true.