Ashley, that is the Properties panel, not the Gradient Editor. Adobe decided the Gradient tool should be able to add a Gradient Fill layer, which can be modified on the fly via the Properties panel. "Classic" Gradients are not adjustable once applied, but don't create a new layer. They're all the same Gradients, of course, bu vary in how they are applied.
I was able to edit and save a new Gradient via the Properties panel, but it was like I was wearing boxing gloves. I prefer the Classic editor, because the Color and Opacity stops are on either side of a single bar, which makes it easier to see how they line up. On the Properties version you can't select colors from the Swatches panel, only from the image or the Gradient in the panel.
I know of two ways to access the Gradient Editor: First, with a layer that is not a Gradient Fill layer selected choose the Gradient tool set to Classic Gradient, and click on the Gradient shown in the selection box (not the little drop-down arrow).
For a Gradient Fill layer, double click on the layer thumbnail in the Layers panel, which brings up the Gradient control panel dialog. From there, click on the gradient as above (not the little arrow).
... View more