Maybe "caret browsing" is enabled? Could you take a look on the Options page: * Mac: "3-bar" menu button (or Firefox menu) > Preferences * Windows: "3-bar" menu button (or Tools menu) > Options * Linux: "3-bar" menu button (or Edit menu) > Preferences * Any system: type or paste '''about:preferences''' into the address bar and press Enter/Return to load it In the tiny search box at the top of the page, type ''cursor'' and Firefox should filter to the "Browsing" section. If the box is checked for "Always use the cursor keys to navigate within pages" then uncheck that box. <img src="https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2020-07-15-13-03-03-35f88d.png"> If you changed that, does it make any difference? ---- There also is another way to manage this feature that is a little more under the covers: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button accepting the risk. (2) In the search box in the page, type or paste '''caret''' and pause while the list is filtered (3) If the '''accessibility.browsewithcaret''' preference is bolded and has a value of true, double-click it to restore the default value of false (4) If you do not want the F7 key to switch this feature on and off, double-click the '''accessibility.browsewithcaret_shortcut.enabled''' preference to switch the value from true to false More info on about:config: [[Configuration Editor for Firefox]]. Hope that helps!