Did you make sure your mouse driver and mouse software isn't the cause of the problem? Those zoom in and out would require the mouse driver and software installed to cause those effect or was corrupted and thus the action of the mouse is misinterpreted for feedback.

uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Reinstall with Current Release Firefox 57.0.4 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

@WestEnd,

Thanks for the reply\suggestions. I am using an iMac, and I am not sure how to check\update the mouse drivers. I also just today found out that it does not seem to be a Firefox issue as it happened in another app also. I will look into 'mouse stuff'.

Wil Dieteren

@Pkshadow,

Thanks for the reply\suggested fix. As I mentioned, this has been happening on with a number of Firefox versions, so I do not think uninstalling\reinstalling will help. I also just today found out that it does not seem to be a Firefox issue as it happened in another app also. So I will need to look for a solution elsewhere.

Wil Dieteren