diff --git a/invesalius/gui/task_slice.py b/invesalius/gui/task_slice.py
index 7a78c50..138e70b 100644
--- a/invesalius/gui/task_slice.py
+++ b/invesalius/gui/task_slice.py
@@ -468,8 +468,8 @@ class MaskProperties(wx.Panel):
 
     def OnComboThresh(self, evt):
         (thresh_min, thresh_max) = Project().presets.thresh_ct[evt.GetString()]
-        self.gradient.SetMinValue(thresh_min)
-        self.gradient.SetMaxValue(thresh_max)
+        self.gradient.SetMinValue(thresh_min, True)
+        self.gradient.SetMaxValue(thresh_max, True)
 
     def OnSlideChanged(self, evt):
         thresh_min = self.gradient.GetMinValue()
diff --git a/invesalius/gui/widgets/gradient.py b/invesalius/gui/widgets/gradient.py
index d061942..5da77d0 100755
--- a/invesalius/gui/widgets/gradient.py
+++ b/invesalius/gui/widgets/gradient.py
@@ -577,20 +577,22 @@ class GradientSlider(wx.Panel):
         self.slided = 0
         self._GenerateEvent()
 
-    def SetMinValue(self, value):
+    def SetMinValue(self, value, do_event=False):
         try:
             value = value.data
         except AttributeError:
             pass
+        self.slided = 0 if do_event else 1
         self.GradientPanel.SetMinValue(value)
         self.SpinMin.SetValue(int(value))
         self.GradientPanel.Refresh()
 
-    def SetMaxValue(self, value):
+    def SetMaxValue(self, value, do_event=False):
         try:
             value = value.data
         except AttributeError:
             pass
+        self.slided = 0 if do_event else 1
         self.GradientPanel.SetMaxValue(value)
         self.SpinMax.SetValue(int(value))
         self.GradientPanel.Refresh()
--
libgit2 0.21.2