Often when I am using variable radius, I select an edge, then try to enter the radius I want by clicking on the little flag that is attached to each end of the line segment.  Sometimes when I do that, the flag jumps out of the view totally, so it can't be selected.  If I zoom out so that I can see it, then maybe I can pick it, but I want it to stay put and let me select it in whatever zoom level I want.  Sometimes when you zoom out in Variable Radiu, all those flags get crowded on top of each other, and it's a big mess that takes time to untangle to even find the one you want!