I'm running 32-bit Windows 7 Home Premium and are now using Firefox Quantum (v57.0). Just now I experienced a strange bug. My home page is msn.com and after closing a tab after playing a video from that site I found that the audio of the next video to be played started playing. Not being 100% sure what tab was playing the audio I started closing tab after tab but the audio continued to play. In fact, the audio still played even after I closed the browser itself! It even started to play the audio of (what I had to assume was) the next video in line. I finally had to call up Windows Task Manager to delete the two remaining instances of Firefox (the process, not the program) that were still running. That brings up a good point. For many months now, when I browse with Firefox it creates many instances of itself (as many as 8-10) at one time, even though the desktop shows only one instance running. Is this normal? Is it necessary? In the past this seems to have slowed Firefox down tremendously, even hanging it at times. Fixing this (temporarily) required that I close the browser, open Task Manager and delete the remaining processes. Quite an inconvenience, to be sure! Now that I'm using the much faster Quantum, I'm worried that this will continue to happen. Any advice you can give me?