After months of banging my head and fingers, it is like so:
Main behavior:
Prtscn => Saves Full screen to folder [default ~/Pictures]
Modifiers
- +Ctrl => Saves to clipboard
- +Alt => Saves current window
- +Shift => Draws area to save
And all combinations. [except alt + shift which behaves like alt alone]
For Example:
Ctrl + Shift + Prtscn will let you select area and save it to clipboard