Colors
The library swatches, and the colors the drawing paints

The Colors panel of the resource column, with its grid of colours

What it lists

By default, the library swatches, each with its name in the tooltip. With Document in the menu, the colors the drawing actually paints — the effective fill and stroke of visible shapes and texts, inherited ones included, currentColor and the default black. A stroke counts only if it has a width. The most used comes first, and the tooltip says how many objects use it.

The document colors do not include gradients, patterns, images, the colors of color stops or those of individual runs of a text.

Gestures

GestureWhat it does
Click, ⌘ + click, ⇧ + clickselect colors in the panel
Double-click a library swatchapplies it as fill to the selected objects; with ⌥ as stroke. With nothing selected it becomes the color you draw with
Double-click a document colorselects on the canvas the objects that use it as fill and frames them; with ⌥ those that use it as stroke
Drag a color onto a shapedropped on the outline it becomes its stroke, inside it becomes its fill
Type a color in the footeronly with the document colors: recolors everywhere. Every fill and stroke of that color takes the new one, in one step. The old color's transparency is kept if the new one has none; an invalid color does nothing

The menu

The ≡ in the header: Document switches from the library to the document colors and back; Select users, only with the document colors, selects on the canvas the objects that use the selected colors, even more than one.