Not sure about you, but I have been having a frustrating issue with Firefox (I am a Mac user) for the last 6 months or so. Browsing a page, for no reason, a contextual menu would pop up. For months I thought is was from a fix I had made on the keyboard and did not realize it was only happening in the browser. Has anyone else had this issue? I found a fix. See below:
Thanks to the infinite wisdom of Steve Jobs,
many Macs have only one mouse button. Once again, the good people at
Mozilla have ignored a fundamental feature of the Mac UI.
Here’s the solution: type in your browser: about:config, and search for ui.click_hold_context_menus. Double click where it says “false” to set it to “true”, and now you’ll get the context menu by holding the mouse button.
It's working for me and I am so happy to find a fix!