To add an "Add Element" keyboard shortcut without having to create something new, maybe something like this would work:
Register a keyboard shortcut, for example Ctrl + A or Cmd + A
Hook it up so it triggers the "Add Element" + button
After the "Add Element" panel is open, and the "Fillter selected folder" field is focused, register the Enter key to add the first element in the filtered selection
From Discord:
To add an "Add Element" keyboard shortcut without having to create something new, maybe something like this would work:
Ctrl + AorCmd + AEnterkey to add the first element in the filtered selection