Tab Isolation

To improve reliability, Internet Explorer 8 features a new process known as Loosely Coupled Internet Explorer (LCIE). This process model also requires a new session model. Each tab is a separate process, and if a single Web page crashes, Windows will close only the one tab. Instance of Internet Explorer 8 with four processes: one for the frame and one for each of the three tabs. Each portion of the window that is represented by a separate process is boxed. Unlike Internet Explorer 7, Internet Explorer 8 can host tabs when Protected Mode is both enabled and disabled within a single browser window.

All tabs and browser instances share a single session, however. This means that different tabs and different browser windows will, by default, use the same set of cookies.

Internet Explorer 7 uses different sessions for different browser windows. Therefore, a user can log on to a Web site as User1 in a browser window, open a second browser window, and log on to the same Web site as User2. In Internet Explorer 8, the user is automatically logged on as User1 in the second browser window. If the user logs out and then logs back on as User2 in the second browser window, they are also be logged on as User1 in the first browser window.

To work around this, the user can start a new session in a new browser window by clicking the File menu and then clicking New Session. Alternatively, you can start Internet Explorer 8 by using the -nomerge command-line parameter. For example, you can replace the standard Internet Explorer 8 shortcut with a shortcut to Iexplore.exe-nomerge.

When using Internet Explorer 8 in Windows 7, Windows 7 uses a timer to detect tabs that might be nonresponsive. If a tab doesn't respond within a given interval of time, Internet Explorer 8 allows the user to choose to cover the tab, close the page, or wait for the tab to respond.