Click 'Customize sidebar' at the bottom of the sidebar, then select Show and hide sidebar. Now the sidebar button next to the address will disable the sidebar.

Here's an illustration to go along with the above steps.

Did this and the Side Bar was NOT REMOVED!

Did this and the Side Bar was NOT REMOVED!

Hi Newbie, try clicking the toolbar button again once or twice. After the settings change, it's a toggle to show/hide.

If you don't have the toolbar button, you can add it using Customize (Customize Firefox controls, buttons and toolbars):

delete this reply

there is no 'hide sidebar.'

Public caning for the person who put this on my screen without an easy way to remove it.

there is no 'hide sidebar.'

What version of Firefox are you running? The Settings page (sometimes known as the Preferences page) has this new section recently:

When that box is checked, there is a persistent vertical button bar (the launcher). When it is cleared, there isn't.