diff --git a/invesalius/data/viewer_volume.py b/invesalius/data/viewer_volume.py
index 0b92927..82f1c4b 100755
--- a/invesalius/data/viewer_volume.py
+++ b/invesalius/data/viewer_volume.py
@@ -140,6 +140,7 @@ class Viewer(wx.Panel):
             
         self.mouse_pressed = 0
         self.on_wl = False
+        self.slice_plane = 0
         
 
     def OnHideText(self, pubsub_evt):
--
libgit2 0.21.2