'autofill objects' mode ignores 'preserve labels'

Describe the bug I have 'autofill objects' activated as well as 'preserve labels' from the labeling GUI. If I draw next to an existing label, the label is preserved while drawing but the fill mode sometimes ignores it so that some already labeled pixels get relabeled.

To Reproduce Steps to reproduce the behavior:

'autofill objects' activated
'preserve labels' activated
draw one labels (convex/concave shapes make the issue more obvious)
draw another label next to it

Expected behavior I would expect the existing label remains untouched.

napari info

napari: 0.4.15
Platform: macOS-10.13.6-x86_64-i386-64bit
System: MacOS 10.13.6
Python: 3.9.7 (default, Sep 16 2021, 08:50:36) [Clang 10.0.0 ]
Qt: 5.15.2
PyQt5: 5.15.6
NumPy: 1.21.5
SciPy: 1.8.0
Dask: 2022.02.0
VisPy: 0.9.6

OpenGL:
- GL version: 2.1 INTEL-10.36.32
- MAX_TEXTURE_SIZE: 16384

Screens:
- screen 1: resolution 2560x1440, scale 1.0
- screen 2: resolution 1440x900, scale 2.0

Plugins:
- PlatyMatch: 0.0.3
- RedLionfish: 0.6
- animation: 0.0.2
- cellpose-napari: 0.1.4
- clEsperanto: 0.15.4
- console: 0.0.4
- devbio_napari: 0.4.0
- napari-3d-ortho-viewer: 0.0.1
- napari-accelerated-pixel-and-object-classification: 0.6.6
- napari-brightness-contrast: 0.1.6
- napari-clusters-plotter: 0.2.2
- napari-crop: 0.1.5
- napari-curtain: 0.1.1
- napari-folder-browser: 0.1.3
- napari-itk-io: 0.1.0
- napari-ome-zarr: 0.3.2
- napari-plot-profile: 0.2.1
- napari-plugin-search: 0.1.3
- napari-segment-blobs-and-things-with-membranes: 0.2.17
- napari-simpleitk-image-processing: 0.2.1
- napari-tabu: 0.1.5
- napari-time-slicer: 0.4.3
- napari-tools-menu: 0.1.10
- napari-workflow-optimizer: 0.1.3
- napari_skimage_regionprops1: 0.2.9
- napari_skimage_regionprops2: 0.2.9
- scikit-image: 0.4.15
- svg: 0.1.6

bauerdavid / napari-nD-annotator

'autofill objects' mode ignores 'preserve labels' #28