Use layer colours to change the UI display colour of all object's path, nodes and handles within a chosen layer.
Objects drawn outside of layers will adopt a default blue wireframe path, nodes and handles. For any layer you create, it will be assigned the same default blue colour but you can assign a different colour to the layer at any time. This means that any tool you use while drawing new objects or editing objects in that layer will adopt the current layer colour.
For reference, the layer colour is shown as a coloured strip directly under the layer entry in the Layers panel.
Use layer colours to either help visually identify which layer you're working on or to help distinguish an object's path, nodes and handles from low colour-contrast surroundings. For the latter, if you're drawing something blue (for example), the default layer colour of blue would mean that your object's path, nodes or handles could be hard to see, so choosing a different layer colour, e.g. orange, would improve UI visibility when you worked with objects on that layer.
Any object drawn in the layer will display paths, nodes and handles in that layer's layer colour.