2. Basics of Image Processing / 2.3 Layers
If you apply operations such as union or difference on vector layers (see chapter 7.4.41 ff.), the result is a path group.
A path group is a mixture of a group (see chapter 2.3.5) and a vector layer. It contains all vector layers involved, but you can also assign a fill color and an outline style.
The vector layers in the group can be edited later and the result of the vector operation is automatically updated.
You can also drag additional vector layers into the path group and assign an operation to them via the layer list (see chapter 4.7).
The following example shows a path group with two circles and a rectangle in between. The left circle and the rectangle were merged and the right circle was subtracted from the result. The original vector layers are drawn with reduced intensity:
If you want a normal vector layer instead of a path group, you can use either the menu commands "Layer > Fix Layer" or "Layer > Convert Layer Type".
Tip: Path groups also support virtual copies (see chapter 2.3.6) of vector layers.