As Firefox often responds slow to my actions on my Compaq Presario CQ5303NL I have tried solving this by raising the priority of some of the 8 to 10 firefox.exe processes from Normal to High (with 3 Firefox windows and about 20 tabs open). This is done with the Task Manager. However the last month every 10 to 20 minutes the priority settings are reversed and about four firefox.exe processes are then set to Low priority at regular time intervals. This also seems to result in slow response to mouseclicks. Are you aware of this phenomenon? Is this something Firefox does by itself, or is this intervention coming from Windows 10. I notice that when I put explorer.exe in high priority, this lasts till shutdown of the computer, as with other manageble processes.

This is not a serious problem. It's more questioning what Windows is doing with Firefox. (memory is 6GB)