- fix the scrolling and allow the snapshot mangager form to be scrolled
  using cursor keys irrespective of the keyboard repeat speed
- reload preview form after the screenshot is deleted using the menu
- prevent the current machine machine to be added to the list of machines 
  to share snapshots with when using mDNS discovery
- prevent the preview form from stealing focus
- display notes even if a snapshot does not have any screenshot
- allow the user to edit and delete notes
- make sure that the right click button selects a different row if no other
  rows have been selected or just one row is selected (the snapshot manger
  menu only operates on currently selected items)