Scrolling with arrow keys no longer works

This article describes solutions to Firefox, Mozilla Suite, and SeaMonkey not scrolling web pages when you press the arrow keys. If the scroll bar is gone, see Scrollbar gone instead.

You may have inadvertently enabled Caret Browsing. When Caret Browsing is on, web pages act like word processor documents, with a blinking vertical bar that shows you where in the document you are. To turn Caret Browsing off, press F7.[1]

To prevent people from accidentally turning on Caret Browsing when pressing F7, the application will show a confirmation dialog:

If you selected "Do not show this dialog again", you can bring this warning dialog back by setting accessibility.warn_on_browsewithcaret to true:

1. Type about:config in the Location Bar.
2. Press Enter.
3. Find the preference name accessibility.warn_on_browsewithcaret.
4. Double click on it to set it to true.

To reduce such problems in the future, you can add the following in your User.js file so that every session begins with Caret browsing off.

// Get SpaceBar, PageUp, PageDown to work properly if F7 hit accidentally
user_pref("accessibility.browsewithcaret", false);
user_pref("accessibility.warn_on_browsewithcaret", true);