unable to change viz 'Style' (color, size, shape, etc.)

I uploaded a new dataset ('Permits by month') and visualized it. I choose an attribute to display ('category') and encode 'all unique values' - of which there are 5 represented - using either 'Default' or 'Autumn' palette. So far, so good.

BUT I can't change the 'icon' for my data-points: I right-click on the 'icon' and get the 'Style Picker' pop-up menu (colors, shapes, sizes, etc.), but after clicking 'OK' the attributes remain unchanged. (FWIW: I can switch back and forth between Default and Autumn, and I do see changes. It's only when I try to modify color, etc., that it fails to work as designed.)