diff --git a/rtengine/LUT.h b/rtengine/LUT.h
index 60ccd8b91..67fb4fade 100644
--- a/rtengine/LUT.h
+++ b/rtengine/LUT.h
@@ -122,7 +122,7 @@ public:
 		clip = flags;
 	}
 
-	LUT<T> & operator=(const LUT<T> &rhs) {
+	LUT<T> & operator=(LUT<T> &rhs) {
 	    if (this != &rhs) {
 	      if (rhs.size>this->size)
 	      {
diff --git a/rtengine/rtthumbnail.cc b/rtengine/rtthumbnail.cc
index 7f5954295..d433c840a 100644
--- a/rtengine/rtthumbnail.cc
+++ b/rtengine/rtthumbnail.cc
@@ -746,7 +746,7 @@ IImage8* Thumbnail::processImage (const procparams::ProcParams& params, int rhei
     for (int i=0; i<fh; i++)
         for (int j=0; j<fw; j++){
             hist16[CLIP((int)((labView->L[i][j])))]++;
-            hist16C=CLIP((int)sqrt(labView->a[i][j]*labView->a[i][j] + labView->b[i][j]*labView->b[i][j]));
+            hist16C[CLIP((int)sqrt(labView->a[i][j]*labView->a[i][j] + labView->b[i][j]*labView->b[i][j]))]++;
 			}
     // luminance processing
 //	ipf.EPDToneMap(labView,0,6);