diff --git a/js/annotator.js b/js/annotator.js
index 8f92ca4..7295e47 100644
--- a/js/annotator.js
+++ b/js/annotator.js
@@ -37,7 +37,9 @@ H.Annotator = function () {
 H.Annotator.prototype.grow = function(i, j, k) {
   let intensity = this.getVolumePixel(i, j, k);
   
-  let mn = intensity * (this.threshold_tolerance / 100);
+  // More restrictive bounds to prevent growing into bone/tissues
+  let tolerance_factor = this.threshold_tolerance / 100;
+  let mn = intensity * (1 - tolerance_factor);  // Lower bound: intensity - tolerance
   let mx = intensity + this.threshold;
 
   H.D.nv.drawPt(...[i,j,k], H.D.label);
diff --git a/js/viewer.js b/js/viewer.js
index e0b4243..0129ac5 100644
--- a/js/viewer.js
+++ b/js/viewer.js
@@ -67,16 +67,27 @@ H.Viewer.prototype.setupWLSlider = function(v) {
   // setup WL slider
   var slider = document.getElementById('wlslider');
 
-  noUiSlider.create(slider, {
-      start: [v.global_min, v.global_max],
-      behaviour: 'drag',
-      connect: true,
+  // Reuse existing slider if present; update its range for the new volume
+  if (slider.noUiSlider) {
+    slider.noUiSlider.updateOptions({
       range: {
-          'min': v.global_min,
-          'max': v.global_max
-      },
-
-  });
+        'min': v.global_min,
+        'max': v.global_max
+      }
+    }, false);
+    H.V.sliderWL = slider;
+  } else {
+    noUiSlider.create(slider, {
+        start: [v.global_min, v.global_max],
+        behaviour: 'drag',
+        connect: true,
+        range: {
+            'min': v.global_min,
+            'max': v.global_max
+        },
+
+    })
+  };
 
 
   H.V.sliderWL = slider;
@@ -130,5 +141,4 @@ H.Viewer.prototype.reset = function() {
   var wl = H.V.getWLFromMinMax(130, 1500); // HU BONE!
   H.V.updateWL(wl[0], wl[1], true); // propagate to UI + volume
 
-};
-
+};
\ No newline at end of file