Palette

Palette is a special layer for picking color.
To show palette layer hold C key on keyboard.
You can then click anywhere on the layer to sample color from it.

Snap for Palette feature can be accessed in layers panel
Options->Snap for Palette
This feature allows to add image/color to palette layer in a live session.
1. Select a layer, that contains an image or color you would like to add to palette.
2. Pan and zoom canvas to position and scale content;
3. do Options->Snap for Palette in layers panel
(!) Snap for Palette will imprint the canvas view onto a palette

(contents of a selected layer will be imprinted onto a palette layer, of the scale and position same way you see them in canvas view)

Palette Library is a menu for managing palette presets
Access it in Other->Palette Library
Capture feature in palette library allows to capture current state of palette layer into a preset.
You can also export any preset as a .png image file.

note: resizing program window will also resize and re-position contents of a palette layer