F5 — reload the page and display the form for loading image again
ENTER — stop polygon drawing (or click on first helper)
ESC — cancel drawing of a new area
SHIFT — square drawing in case of a rectangle and right angle drawing in case of a polygon
DELETE — remove a selected area
ESC — cancel editing of a selected area
SHIFT — edit and save proportions for rectangle
i — edit attributes of a selected area (or dblclick on an area)
↑ — move a selected area up
↓ — move a selected area down
← — move a selected area to the left
→ — move a selected area to the right
