Here I came up with another utility named: "View/Add/Edit Atlas in Full Screen Mode"
If this does not work as IRI link save this file and open in browser
Enjoy..
Have you tough of seeing Atlas in full screen mode while editing so that you does not click somewhere by mistake and discard your effort.
Also...
more... facing screen space concerns and scrolling for your changes.
Here is the solution just enter route numeric number in textbox and click Go, It will redirect you corresponding route you can edit it and press save.
This depends fully on IRI Atlas so if IRI site is down it wont work.