When you have finished using one-X Portal, you should click on the Logout link shown in the top right. This will end your session and return the browser to the log in screen. If you used portal to login to an extension, you will be prompted whether you also want to log out from the phone you are using.

If you simply browse to another website, your browser's back, forward and history functions can be used to return to your portal session without needing to log in again. While this can be useful to you, it is a risk if you use the portal from a shared computer or one in a publicly accessible location. After you have finished using the portal, always use the Logout control and close the browser.