diff --git a/rtengine/rt_algo.cc b/rtengine/rt_algo.cc
index 975b08374..8472fb858 100644
--- a/rtengine/rt_algo.cc
+++ b/rtengine/rt_algo.cc
@@ -269,8 +269,10 @@ void buildBlendMask(float** luminance, float **blend, int W, int H, float &contr
                 const int minY = tilesize * minI;
                 const int minX = tilesize * minJ;
 
+//                std::cout << pass << ": minvar : " << minvar << std::endl;
                 if (minvar <= 1.f || pass == 1) {
                     // a variance <= 1 means we already found a flat region and can skip second pass
+                    // in second pass we allow a variance of 2
                     JaggedArray<float> Lum(tilesize, tilesize);
                     JaggedArray<float> Blend(tilesize, tilesize);
                     for (int i = 0; i < tilesize; ++i) {
@@ -278,8 +280,7 @@ void buildBlendMask(float** luminance, float **blend, int W, int H, float &contr
                             Lum[i][j] = luminance[i + minY][j + minX];
                         }
                     }
-
-                    contrastThreshold =  std::min(contrastThreshold, calcContrastThreshold(Lum, Blend, tilesize, tilesize) / 100.f);
+                    contrastThreshold = (pass == 0 || minvar <= 2.f) ? calcContrastThreshold(Lum, Blend, tilesize, tilesize) / 100.f : 0.f;
                     break;
                 }
             }
diff --git a/rtgui/bayerprocess.cc b/rtgui/bayerprocess.cc
index 9b5ffece2..f9b6ef9e5 100644
--- a/rtgui/bayerprocess.cc
+++ b/rtgui/bayerprocess.cc
@@ -312,6 +312,9 @@ void BayerProcess::read(const rtengine::procparams::ProcParams* pp, const Params
     lmmseIterations->setValue (pp->raw.bayersensor.lmmse_iterations);
     dualDemosaicAutoContrast->setValue (pp->raw.bayersensor.dualDemosaicAutoContrast);
     dualDemosaicContrast->setValue (pp->raw.bayersensor.dualDemosaicContrast);
+    if (!batchMode) {
+        dualDemosaicContrast->set_sensitive(!pp->raw.bayersensor.dualDemosaicAutoContrast);
+    }
     pixelShiftMotionMethod->set_active ((int)pp->raw.bayersensor.pixelShiftMotionCorrectionMethod);
     pixelShiftEperIso->setValue (pp->raw.bayersensor.pixelShiftEperIso);
     pixelShiftSigma->setValue (pp->raw.bayersensor.pixelShiftSigma);
@@ -622,6 +625,9 @@ void BayerProcess::imageNumberChanged ()
 void BayerProcess::checkBoxToggled (CheckBox* c, CheckValue newval)
 {
     if (c == dualDemosaicAutoContrast) {
+        if (!batchMode) {
+            dualDemosaicContrast->set_sensitive(newval == CheckValue::off);
+        }
         if (listener) {
             listener->panelChanged (EvDemosaicAutoContrast, dualDemosaicAutoContrast->getValueAsStr ());
         }