web dynpro IE opens application without user/password

Hello Experts,

In my web dynpro application users have to log on with their SAP user and password.

When I close the application (close tab), but the Internet Explorer is still open (with other tabs) and I reopen my web dynpro application, I don not have to enter user and password again, the application just opens without.

When I totally close Internet Explorer (all tabs) and then open my web dynpro I have to enter User and Password.

For security reason user / password should be entered every time I open my web dynpro application, how can I achieve that.

Thanks

Elko Hasse