Did you try to click Restore Default on the customize page? *https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars Do you see "Take Screenshot" if you right-click on a webpage? Make sure that Screenshots isn't disabled. You can check these prefs on the <b>about:config</b> page (both should be false). *extensions.screenshots.disabled = false *screenshots.browser.component.enabled = false Taking screenshots can also be disabled via a policy (see about:policies). You can open the <b>about:config</b> page via the location/address bar. On the warning page, you can click "Accept the Risk and Continue" to open about:config. *https://support.mozilla.org/en-US/kb/about-config-editor-firefox