It would be nice if you could add a new css property to the applied list via manually typing just like you can do in the perspective property editor.

I usually create an empty style in the designer and style the class in my css custom theme folder by adding the psc- prefix. Then I apply to the necessary components. Plus the some of of the element states are missing from the GUI and I have to add via css (::before and ::after)

It's not a necessity but I would prefer having the option style an a class by typing what I want instead of navigating through drop boxes and a GUI. It's a lot faster