I'd like the user documentation to include information on how exactly the interval is determined when "Take activity into account" is selected. For example, if I use "Short break every: 20 minutes", what is the upper bound until the next break prompt, if I don't enter any keystrokes or mouse movements? What's the lower bound if I have a lot of activity? Can activity (or lack thereof) alter the interval to be longer than the set value, shorter, or both?