Is there a way to assign any generic toggle button as a "shift" button in az controller ?
Shift, Alt, Caps-lock, combinations, knob as multi-mode switch, etc.
The idea is to define Software Set(s) and use them as conditions in other elements, so they perform different things in different states of this set (these sets).
That the "shift" button just has to set/unset corresponding state (as toggle for "caps-lock" like functionality, momentary (set when pressed, unset when release) for "shift" like functionality, etc.).
"ACT MIDI Explained" tutorial has the examples with explanation. Almost all other presets (including Startup) use that.