Some parameters are lists.
I'm trying to remember how to switch between them quickly! For example SHIFT +/- for Blending mode.
Without having to open the list every time and select the next item with mouse click. Just one press to the next parameter.
All standard lists in Windows work in a similar way with up/down keys.
I think before I did it, but now it is impossible.
It was never possible in AE, since it tracks the context of a selected property control and least of all was it ever possible in effects. When a pop-up control is selected, you can of course use the up and down arrow keys.
I think you might be mistaking the blend modes in the effect controls for the blend modes for layers in the timeline... now, THOSE have a keyboard shortcut. But like you, I forgot it.
no. this image only for example
I mean all lists in all plugins.