Using the Multilabel segmentation plugin view and the Corrector 2D tool, a label set image with multiple layers is not correctly handled.
If the Corrector 2D tool is used on any layer, the active label of the first layer is always used.

To reproduce:

1. Load an image, open the multilabel segmentation plugin view, create a new label set image
2. create a new label on the first layer (automatic popup dialog)
3. create another label on the first layer
4. create a new layer and create a third label on that layer (automatic popup dialog)
5. select a specific color for the third label
6. use the corrector tool on the third label (second layer)
   1. in order to do this you first need you create a mask, e.g. by using the "Add"-tool first

See how the corrector tool does not modify the initially created mask.

This only works if the second label on the first layer was activated and then the layer was changed.
The reason is that the layers are not respected by the tool so the active label is the second label, which does not exist on the second layer.

If you want to see the expected behavior, create a segmentation mask on the first label using the "Add"-tool and modify this mask with the corrector tool.