https://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=34134

diff --git a/MagickCore/vision.c b/MagickCore/vision.c
index eeaaf3dfb1399264d070ea8855e2318965a4f598..1d06a8b390bbc85d0f177abb8f7985bc6b90fe3d 100644 (file)
--- a/MagickCore/vision.c
+++ b/MagickCore/vision.c
@@ -585,6 +585,7 @@ MagickExport Image *ConnectedComponentsImage(const Image *image,
         if (object[i].census != 0)
           continue;
         component_image->alpha_trait=BlendPixelTrait;
+        component_image->colormap[i].alpha_trait=BlendPixelTrait;
         component_image->colormap[i].alpha=(MagickRealType) TransparentAlpha;
       }
     }
@@ -614,6 +615,7 @@ MagickExport Image *ConnectedComponentsImage(const Image *image,
         for ( ; first != (last+step); first+=step)
         {
           component_image->alpha_trait=BlendPixelTrait;
+          component_image->colormap[first].alpha_trait=BlendPixelTrait;
           component_image->colormap[first].alpha=(MagickRealType)
             TransparentAlpha;
         }