Will its value remains the same during the entire login session for an user?

I have some logic to be executed only when the salesforce user has logged in for the first time. I don't want the logic to be executed on every page refresh.
Is there any way to determine the salesforce user first time login?

I have set the session timeout value to 30 min and enabled "force logout on session timeout" in session settings. I have logged in a salesforce user and kept him idle for more than 30 min. After 40 min, i refreshed the page and noticed that the salesforce session id is being changed and the salesforce session is still active and doesn't logout the user. I didn't also get any warning for the session timeout. Please note that i have not enabled the option "Disable session timeout warning popup". 

Can anyone help me on why the user is not logged out eventhough the force logout is enabled? Is there any way to find whether its a new session or renewed session?

I am using the salesforce console integration toolkit api method sforce.console.setCustomConsoleComponentButtonIconUrl to change the default phone icon in footer console view. I am getting the response as successful but the icon is not getting changed.

Can anyone help me on how to change the default icon in console view?

We have created a custom visual force page (unmanaged) where softphone is not loading. We are getting the below error while opening the visual force page

Uncaught SecurityError: Blocked a frame with origin "https://ap2.salesforce.com" from accessing a frame with origin "https://c.ap2.visual.force.com". Protocols, domains, and ports must match.

However, softphone is successfully loading on other tabs such as Home,Contacts,Accounts etc. We have ensured that the open CTI call center file is assigned to the user and sidebar is set to true in visual force page.

Can anyone help me on this