you are looking for:
/* CRUD floating group on page fixed position */
.fixed-page {
position: fixed!important;
}
youll need to add a class or ID to the page where you want this to be fixed… there are a number of ways to do it, but this is one way.
if you add an html element to the page and make it 0px wide, 0px high.
then add:
Add the Classify plugin ( you dont need this, but you will in the future, if you havent already)
now in the popup or floating group create a text state called ‘fixed page’ - or whatever.
When you trigger open the popup change the ‘fixed page’ state text to: {tempClass: “my-class”}
When you close the popup, fg, just clear the state (make it empty, nothing) - this uses the new temp classed in Classify.
On the page add the state of the fg, or popup you created above.
This should do it for you. (ill assume your a fellow aussie 
by the name)