New sampling modes (beyond point sample) - average 3x3, 5x5, 11x11, 25x25 pixels - new in v3
Ability to sample average color of any selected area (can average images, noisy backgrounds etc.) - new in v3
Allow sampling colors from local "file://" URLs
Auto-start sampling immediately by default on Mac when main button clicked
Allow sampling colors from images opened in a separate tab
Better name for "Copy Special" menu to indicate various Copy options and formats
Add "rgba" format to Copy Special options
Keep the ColorZilla sampling panel consistent size even in zoomed views
New setting to prevent document from being moved down when sampling
Fixed support for Retina displays
Fixed support for sampling in zoomed view
Fixed persisting of add-on settings with certain browser configurations
Fixed copying to clipboard from Copy Special menu
Fixed hexa lowercase / uppercase option
Many tweaks and bug fixes

Tweaks and compatibility fixes.