diff --git a/invesalius/data/mask.py b/invesalius/data/mask.py
index e076d56..2a5457f 100644
--- a/invesalius/data/mask.py
+++ b/invesalius/data/mask.py
@@ -317,7 +317,6 @@ class Mask():
         print "Creating mask at", self.temp_file
         shape = shape[0] + 1, shape[1] + 1, shape[2] + 1
         self.matrix = numpy.memmap(self.temp_file, mode='w+', dtype='uint8', shape=shape)
-        proj.save_workdir()
 
     def clean(self):
         self.matrix[1:, 1:, 1:] = 0
diff --git a/invesalius/project.py b/invesalius/project.py
index 73f468d..154cfc7 100644
--- a/invesalius/project.py
+++ b/invesalius/project.py
@@ -110,6 +110,7 @@ class Project(object):
         """
         index = len(self.mask_dict)
         self.mask_dict[index] = mask
+        self.save_workdir()
         return index
 
     def RemoveMask(self, index):
@@ -121,6 +122,7 @@ class Project(object):
                 new_dict[i-1] = self.mask_dict[i]
                 new_dict[i-1].index = i-1
         self.mask_dict = new_dict
+        self.save_workdir()
 
     def GetMask(self, index):
         return self.mask_dict[index]
@@ -129,6 +131,7 @@ class Project(object):
         #self.last_surface_index = surface.index
         index = len(self.surface_dict)
         self.surface_dict[index] = surface
+        self.save_workdir()
         return index
 
     def ChangeSurface(self, surface):
@@ -144,6 +147,7 @@ class Project(object):
                 new_dict[i-1] = self.surface_dict[i]
                 new_dict[i-1].index = i-1
         self.surface_dict = new_dict
+        self.save_workdir()
 
 
     def AddMeasurement(self, measurement):
--
libgit2 0.21.2