1. user
   1. action
      1. CLICK MOUSE
      2. TYPES CHARACTER
      3. SURFACES WINDOW
2. OS platform
   1. detection
      1. actions
         1. user
   2. generation
      1. GUI events
         1. MOUSE CLICKS
         2. KEYSTROKES
         3. PAINT EVENT
   3. determination
      1. receiver
         1. application
         2. window
   4. placement
      1. in
      2. queues
         1. application
         2. event