Spotify gets stuck on loading screen when tab is left
If I have Spotify paused in a tab, and i change to a different tab for even a second, when I return, it is stuck in a Firefox loading screen. I have to extensions that effect Spotify Browser player. This has been happening for about three or four days. Firefox is up to date.
Firefox may unload tabs when you a low on available free physical memory, so that might happen if you get the loading icon.
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 by the *browser.tabs.unloadOnLowMemory preference that you can set to false to disable this feature. Keep in mind that this makes you vulnerable to low memory issues.