diff --git a/invesalius/gui/task_surface.py b/invesalius/gui/task_surface.py
index 9ae7f89..f105003 100644
--- a/invesalius/gui/task_surface.py
+++ b/invesalius/gui/task_surface.py
@@ -527,7 +527,7 @@ class SurfaceProperties(wx.Panel):
 
         self.combo_surface_name.SetItems([n[0] for n in self.surface_list])
         self.combo_surface_name.SetSelection(i)
-        transparency = 100*pubsub_evt.data[4]
+        transparency = 100*pubsub_evt.data[5]
         self.button_colour.SetColour(colour)
         self.slider_transparency.SetValue(transparency)
         Publisher.sendMessage('Update surface data', (index))
--
libgit2 0.21.2