How to make the Window stay on the browser when scroll down?

When the web page is very long, how do I make the Window object visible when I scroll down? I do not have a viewport, so not using the keepInViewport() function.

var windows,w1;
windows = new dhtmlXWindows();
w1 = windows.createWindow(“w1”, 250, 350, 480, 400);

This will set the window at (250,350). I do I make it float as I scroll up and down?

You may call setPosition(x,y) method to deisplay the window in a certain position.