The fact that ZA Pro is off, may only mean parts of it are off, some of the services may well still be running.
What is the Privacy setting, High can cause this conflict ?
Do you have the latest version of ZA Pro as some changes have been made to improve compatibility ?
You can safely lower the privacy settings, especially when using firefox as it has many of the same functions and you can use extensions also for pop-ups/ad blocking, etc.