Internet Explorer 6 for the first time. Also on that date, the browser's usage share was higher than all versions of Safari, Opera and older versions of Firefox with the exception of Firefox 3.6. As a reference, Internet Explorer 9's usage share first exceeded that of Internet Explorer 6 on May 1, 2011 (48 days after release), and Internet Explorer 9 became the second most used version of Internet Explorer for the first time on May 22, 2011 (69 days after release). According to StatCounter, Firefox 4 reached its usage share peak of 16.7% on June 19, 2011. After that date, it started to decline due to weekly trends and the release of Firefox 5. Migration issues Firefox 4 represents a departure in user interface layout and behaviour from previous versions. Users face some issues negotiating these changes, some of which are not documented in the release notes. Firefox button The Firefox button groups the menus in Firefox 4. It is displayed by default on the Windows 7 and Windows Vista operating systems. It can be displayed on other operating systems by selecting "Toolbars" from the View menu and unchecking "Menu Bar". The Menu bar can be restored by selecting "Options" from the Firefox button menu and checking "Menu Bar". Certain menu items, such as "Page Info" and "Import" (for importing bookmarks and other browser data), are not available from the Firefox button menu but remain available from the Menu bar. The Menu bar can be displayed temporarily by pressing and releasing the Alt key. Selecting a Menu bar command or pressing the Alt key again dismisses the Menu bar. Session data A prompt to save the session (tabs and windows) was presented by default in Firefox 3, with the session restored on the next start if the user selected the "Save & Quit" option. In Firefox 4, all sessions are saved. On the next start, the session is available from the History menu. This new feature, called on-demand session restore, overwrites the previous session on exit without prompting. The user can check whether there is a saved session at any time by viewing the History menu item "Restore Previous Session". If it is available (not greyed out) there is a restorable session available. See also Firefox early version history References External links Firefox Nightly Builds Firefox 4 video decoder architecture Rapid Release plans 4.0 2011 software Free software programmed