There is an option to embed external web content into Siebel Client. I am not going to explain how , it is explained very well here. I am going to talk about symbolic URL which is “IFRAME” . You can open it as part of your page or as a popup window.
My Customer wanted another page to be opened as a popup. I choose IFrame option and basically it is all I need to do.
However IFrame didn’t open as a full screen and customer was complaining that he need to click on the “maximize” button (yeahh… such a big efford).
Now popup windows opens in a full screen mode (maximized)